Is there any way to gain equality with the QGD Marshall Defence?

The Marshall is considered dubious since Black essentially just gives up full control over the center.  For that reason, there is no move that would give Black absolute equality after 4. Nf3

There are probably good development schemes that would give Black a playable game, but there is no direct path to absolute equality.  Heck, there's no direct path to complete equality for Black in even the most respected openings, such as the Grunfeld and Slav.  Even in those openings Black has to work to achieve an equal game.

The best development scheme that I know of in the Marshall is the following (after 4. Nf3):

g6, Bg7, 0-0, Nc6, Bg4.  And if White plays e4 at any point, the Knight on d5 retreats to b6.  This gives Black a reasonable game, and I believe it is the most popular system in the reference database.  But even here, White keeps a comfortable edge.


Is a candidate master considered a master?

In the strict realm of FIDE, a 2200 FIDE rated CM is not a master. This is because FIDE's official master title is the FM (2300 FIDE rating).

However, in the US and Canada, a 2200 national rating earns the NM (national master) title. So, if a player had a 2200 FIDE rating but a 2100 national rating, in the strict sense they would not be considered a master. To be a master you must meet the requirements of FIDE or your country's federation.

Most chess players aren't aware of these arbitrary rating thresholds though, and it's likely they would consider anyone with a 2200 rating in whatever system a master (even though this may not be officially true).


Isn't the Bogo-Indian just busted with this line?

Well, the Bogo-Indian as an opening is hardly busted, but the way black played that opening, there is no doubt that white has a huge advantage in the final position.

The main reasons that black gives up the dark-squared bishop are not to lose time, but then, and this is more important, because he can regain some dark-square control by placing the pawns on d6 and e5, and pressure e4. Often the Nd7 can also find a very nice home on c5 since a5 has been played.

The way it was played in that game, black never did that, and black did not even attempt to contest the center. It was a recipe for disaster. The final straw was exposing the huge hole that was created on b5.

 [FEN ""]

 1. d4 Nf6 2. c4 e6 3. Nf3 Bb4+ 4. Bd2 a5 5. a3 Bxd2+ 6. Qxd2 d6 7. Nc3 Nbd7 (7... O-O {The most common move here.} 8. g3 Nbd7 9. Bg2 e5 $14 {Is a main line. } 10. O-O exd4 11. Nxd4 a4 {Securing c5 for the Nd7.}) 8. Rd1 (8. e4 {Why not this immediately? This is the main move.}) 8... b6?! {This is not necessary here, and we are not even sure that the bishop will go on b7, which I tend to doubt...it may come to g4 and trade for a Nf3 even. It also ruled out a later c6, which would have been desirable later after e5.} (8... Qe7 {This is more natural here, aiming again for e5, and removing the Qd8 from the same line as the Rd1 and Qd2 battery.}) 9. e4 Bb7 10. Qc2 (10. Bd3 {Finish development is more natural here, and later if the black king castles short, then the Bd3 will be aimed at right it.}) 10... Qe7 11. Be2 O-O 12. O-O c5? {This just looks wrong. You still want e5, and if d5, then you have Nc5 and a4 solidifying the Nc5's position. Also, this shows how dead the bishop is on b7} 13. d5 exd5 $2 {This natural move really secures white's advantage because the hole at b5 becomes palpable.} 14. cxd5 Rfe8 15. Nd2 $16 {White almost has a significant, and almost winning, advantage.}


Is the tournament leading to some consensus on how good/bad Carlsen's decision was?

Not quite. As others have pointed out, Carlsen's decision was based on factors outside that one game. With a stronger position and a large time advantage, Carlsen most likely could have won game 12, but Caruana had just tied Carlsen in 11 consecutive games, several of which had each player blunder away a significant advantage. Caruana showed he could go toe-to-toe with our Norwegian champion, and so attacking his position would not come without risks.

Meanwhile, a draw effectively changed the championship to a 4-game Rapid tournament (then Blitz if that ended in a tie), where Carlsen is a heavy favorite. While Carlsen and Caruana are roughly equal in standard chess (2835 and 2832 respectively), Carlsen is much stronger at Rapid (2880 and 2789) and Blitz (2939 and 2767). Why extend a game in an even format when a draw moves to a format you're stronger in?

Having said that, the Chess community was not happy at all to see that draw offered (source: I was unhappy). I'll concede it was a technically correct decision, but as someone who had been waiting 11 games for a win, seeing one materialize then simply vanish was frustrating. It left a lot of people asking "What would have happened if Carlsen hadn't offered that draw? How would the game have ended?", and that's the question these games are answering.

In other words, the tournament isn't leading to some consensus on how good/bad Carlsen's decision was. It's leading to some consensus on how good/bad Carlsen's position was.

All in all, the tournament showed that Carlsen had a very good position. After 56 games, black finished with 27 wins, white finished with 3 wins, and there were 26 draws. That's a tremendous advantage. Any grandmaster would be ecstatic to hear that, for a chess engine, their position was only losing in 5% of games played.

What's more, this tournament had given both sides equal time. That's not completely accurate, as Carlsen had a significant lead on time (though I've forgotten just how much). That implies these results are even too conservative, and that Carlsen may have had a larger lead.

Having said that, humans and computers play in very different styles. Because it's winning for a computer doesn't guarantee it's winning for Carlsen (though he's practically a computer anyway), but it does show he had a strong opportunity to win it all in game 12.


Yes, there are a few four-dimensional chess variants:
https://www.chessvariants.com/index/mainquery.php?type=Any&category=4d&usethisheading=Four+(or+more)+Dimensions

Sphinx Chess, by V.R. Parton, is probably the first, c.1970.  Timeline is also described there (it's actually a full 4 spatial dimensions, being 4x4x4x4, plus the "timelines"), as well as my own variant TessChess.

Most 3D chess (at least online) is played by splaying the levels out next to each other, since seeing and reaching between levels may be difficult.  Once you get used to that, it's not so unnatural to put the levels in a grid, and you've got four dimensions.

Also, most 3D chess is on a smaller board than 8x8x8 (8x8x3 or 5x5x5 are common), and higher dimensions similarly shrink the edge length.  This, together with appropriately extending piece movements, get around NoseKnowsAll's density argument.  But, of course they are also right that the game becomes rather different from chess.

V.R. Parton also created a 6-dimensional game, Ecila.  I and others have toyed around with even more dimensions, but it obviously becomes more difficult for the "array of array of arrays" board simulation to work out.


Do top chess grandmasters have significant drawing chances against top engines?

Today's engines running on suitably powerful computers will most likely beat any top grandmaster.

Ratings are essentially numbers assigned to players such that a player is expected to beat some other player (a draw being counted as a half-win) some fraction of the time, based on their difference in rating. An important point is that the absolute ratings are irrelevant: if every player in the world got a 1000-point boost to their rating, nothing fundamental would change.

The mathematical details imply that according to the rating model, no matter how big the difference in rating, the weaker player will still win some fraction of the time. In the case of Elo, we assume that even the lowest-rated player in the world has a 9% chance of beating Magnus Carlsen. This is clearly a flawed assumption, but it's the kind that almost every rating system makes; and it's not too bad anyway, it works well for the most part (i.e. when rating differences aren't too big), and even at the extreme ends, the best human players can still blunder.

However, today's engines beat humans 100% of the time in a fair game (I wouldn't say there's explicit proof, but the fact that they don't even bother to hold such matches anymore says a lot, so let's just say this is true); thus it's completely meaningless to assign a FIDE rating to these silicon monsters: there is absolutely no difference whether a 2800 player meets a 3300-rated engine or a 4300-rated engine, as far as the Elo rating system is concerned. Even for an engine running on a desktop, if we assume that a top grandmaster could score some 5%, we'd still be looking at what statisticians call a tail event; rating systems (and statistics in general) are really bad at these.

So top computer engines have their own rating lists, no humans involved. But they still run on the Elo system, albeit apparently with a different 'base'. You can meaningfully compare engines here; a 100-point rating difference will probably correspond to a sensible winning percentage.

On the other hand, the difference between the FIDE rating list and computer chess rating lists (CCRLs) are completely meaningless. While CCRL base ratings were probably chosen to be higher because most computers are simply better than the best humans, this base rating is just arbitrary (at least as far as I know); we could subtract 2000 points from every rating in the CCRL and add 2000 to every rating in FIDE, and both lists will continue to function the way they have.

It seems that the modern way to compare humans to computers today is to look at scores from matches where players are given a handicap. If I recall correctly, this is reminiscent of the pre-Elo days, when players' strengths were gauged by how they fared against the best players under a handicap!

Long story short: the high ratings are meaningful when compared with other engines in the same list. On the other hand, they are absolutely worthless for comparison against humans.


How do endgame tablebases calculate checkmates to do retrograde analysis on?

Yes, endgame tablebases are calculated by brute force. That's why we only have complete 7-men tablebases today (which were published in 2012).
When stockfish finds a mate with more pieces than stockfish has calculated until only 7 men are on the board and the tablebases give stockfish the solution for the rest.


Am I improving my tactical knowledge by explaining solutons to my wife?

Since you are teaching your wife, who's new at chess, these tactics are perhaps a bit too easy for you. They probably won't do much for your standard game.

That said, by explaining the patterns to her and doing a lot of 'easier' tactics, you are definitely helping your blitz/bullet games.

Basically you'll be able to see tactics faster in your games, but your ability to see more complicated tactics is remaining more or less unchanged. To really hone your tactics, you're going to need to improve your ability to calculate deep, and consider several different lines when perhaps the solution isn't as obvious.

Teaching is great for reminding yourself of the basics, but if you want to improve, you're going to need to do more than teach. Find some more difficult tactics for yourself, play some challenging games, study more opening lines, and analyze your shortcomings.

Hope this answers your question.


Who was the last Indian player to beat Vishy, and when?

The answer is: Yes

Krishnan Sasikiran vs Viswanathan Anand
FIDE World Cup-C (2002), Hyderabad, rd 2, Oct-05
King's Indian Attack: Yugoslav Variation (A07)
1-0

http://www.chessgames.com/perl/chessgame?gid=1357060


It is certainly playable. The main drawback is that you give White the choice between two very different mainline openings:

3.Nf3 transposes to a Sicilian, where Black is already committed to e6 (Kan, Taimanov or Scheveningen, but no Najdorf, Sveshnikov, etc.).
3.d5 reaches a Benoni structure and may transpose to a mainline Benoni if White later plays c4. But in some lines White may profit from not having played c4, e.g. by posting a strong knight on c4 instead.

So you are giving White a pleasant choice, and you don't really gain anything in return. If you are prepared to play the Sicilian, then why not meet 1.e4 with c5 straight away? Sure, White could choose some Anti-Sicilian line, but most true Sicilian players feel that these are not as challenging as the Open Sicilian, so they have no need of a move order that tries to trick White into playing the Open Sicilian.
Additionally, the Benoni is of course far less popular than the Sicilian, which is another reason for your move order being played so rarely.


How do I play 30 second games on chess.com?

Go into Live Chess.
Click on the left button right above the "Play" button. It should currently display some time control.
Click on the "More" button.
Click on the "30 sec" button. For custom time controls, you can instead click on the "Custom" button and enter what you want.


Opening classification and transpositions

Your question has two different nuances, that is, how to classify an opening and how to classify a game.

The Encyclopedia of Chess Openings' only aim is to classify the first moves of a chess game, it does not concern itself with how the game develops nor further transpositions. Even if a widely known position is reached after an unorthodox choice of moves, the ECO will classify the opening according to these first moves. A comprehensive list can be found both in 365Chess and Wikipedia, the first provides easy access to the variation in question and the second provides the name and some contextualization for the variation.

While the ECO has not an analogous encyclopedia for complete games, the widespread and common way of treating them in the literature is to find the last instance of a known tabiya and consider the game under its umbrella. This ignores the concrete opening, which is often useful since the game may be a relevant addition to the theory on that position, and thus the particular move order leading to it is irrelevant.


Why did Bobby Fischer play the Queen's Gambit as White vs. Spassky?

Spassky had an entire squad of Soviet grandmasters trying to find holes in Fischer's repertoire. So it made a lot of sense to surprise them. He also avoided the sharp King's Indian and went for the Nimzo instead.

There are other examples for this strategy. Peter Leko, a 1.e4 player, switched to 1.d4 for his match against Kramnik. Changing the black repertoire is even more common: Gelfands Gruenfeld and Sveshnikov against Anand, Kramniks Berlin against Kasparov ...


Can solving lots of mate in one (or two) problems be beneficial?

There's a wide array of opinions as to the debate on whether simple problems done repetitively, or more challenging problems are better for improvement at tactics.

My personal opinion is that both have their place and both improve different essential things. Getting those simple problems down cold is very good for pattern recognition and board vision, but the more challenging problems improve tactical analysis abilities, problem solving skills, and help prepare a player for tournament situations.

As for whether your collection of thousands of mate in 1 or 2's would be very helpful, I'd say that mating patterns are certainly important to practice but I don't know if you really need to train with quite so many. It certainly wouldn't hurt, but you might have faster growth practicing with the mating problems on chesstempo. They have them tagged and you can create your own sets of problems if you're a member.


How would FIDE handle a player with ADHD in tournaments?

How would FIDE handle a player with ADHD who is rightfully prescribed
amphetamines?

FIDE handles this in the same way as all Olympic sports handle such things. Anybody who follows such sports (particularly cycling) will be familiar with "Therapeutic Use Exemptions" or TUEs.
They are covered in the FIDE Anti Doping Rules:

4.4 Therapeutic Use Exemptions (“TUEs”)
4.4.1 The presence of a Prohibited Substance or its Metabolites or Markers, and/or the Use or Attempted Use, Possession or FIDE Anti-Doping Rules 14 Administration or Attempted Administration of a Prohibited Substance or Prohibited Method, shall not be considered an anti-doping rule violation if it is consistent with the provisions of a TUE granted in accordance with the International Standard for Therapeutic Use Exemptions.

FIDE provides a standard Therapeutic Use Exemptions (TUE) Application Form which can be downloaded from their site, filled in, signed, and submitted.


First thoughts:

We are obviously looking for a win for White. Making a draw is no challenge, you just have to exchange either the rook or your bishop even if you lose all three pawns in the process. 1.d4, 2.Bg6, 3.Bxe8 is a straitforward draw.

If we do nothing dramatic, Black can blockade with ...Kg7 and ...Bd6, when he cannot be worse. So let's go for direct play trying to exploit the pin on the 8th rank:

1.d4 Bd6 (or 1...Bd4 when 2.Bg6 might be the best try but the hand wants to play 2.d6 Rxe6 3.d7 Bf6 (or Bb6) and Black seems to draw thanks to ...Kg7 or ...Rd6+ - looks like a good line in which one can look for pretty ideas...)

2.Bg6 Kg7 (Black can also wait with his bishop, but White will try to bring in his king and maybe create a zugzwang of some sort)

3.Bxe8 (3.Rxe8 Rxe8 4.Bxe8 Kf8 is a dead draw) and with the rooks on the board White may well be able to break the blockade.

Well, there is probably a win hiding somewhere in those lines, but it is not an easy one.


What are all the possible combinations of openings which work well together? (like the Slav+Caro-Kann combo)

I don't think there is a single other opening combo that shares as many features as the Caro-Kann and the Slav. All the other defences against e4 lead to unique pawn structures and piece constellations that aren't easily reached from d4/c4-openings.

Just playing the same move against e4 and d4 either leads to completely different openings (Indian Defences/Alekhine, Sicilian/OldBenoni, French/Whatever) or exactly the same defence (The Modern).

That being said, there are some popular opening-combos, but they usually own their popularity to a similar attitude or character of play.

One such combo would be the King's Indian and the Dragon. The obvious similarity is the fianchettoed bishop and the aggressive attitude.

Another might be the French and the Nimzo-Indian. Both are rather strategic setups with counterplay on the queenside.

The Queen's Gambit declined and 1…e5 would be another sensible combination. The attitude is classical: Equalise first, play for a win later.


Why do players resign after accidentally giving their opponent a free queen?

Material (i.e. basically who has more and better pieces) is a very important factor in the objective evaluation of a chess position. The queen is the strongest piece on the board, roughly equal to two rooks or three minor pieces (knights or bishops).

If you really drop a queen in an otherwise equal position you are going to lose 99.9% of the time. Rarely you have situations where you have compensation for being a full queen down, like for instance you have a very strong mating attack or perhaps the queen is bound to protecting a pawn from queening, etc.

If there is no such compensation it is very reasonable to resign. There is not much point (and not much fun) playing a queen down. In fact most slightly advanced players would resign being a minor piece (knight or bishop) down in otherwise normal position (no attack, etc going on).


The USCF has two independent systems for naming players' levels:

1) Rating-based: Senior Master (2400+), National Master (2200-2399), Expert (2000-2199), Class A (1800-1999), Class B (1600-1799), etc. This describes your current rating; you can be Class A today and Class B next week. The one exception is that once your rating gets to 2200, you are a master forever. These names and rules have been around for decades and are what most players are familiar with.

2) Norm-based: Life Senior Master (2400+), Life Master (2200+), Candidate Master (2000+), 1st Category (1800+), 2nd Category (1600+), etc. You are granted one of these titles by achieving five norms of that level and getting to the minimum required rating (at least once). Generally speaking, a title norm is a tournament performance that would be impressive for someone who had the minimum rating for that tile. These norms are what you see when you look at a USCF player's rating page. The full rules for norm-based titles are available online. One intent of norm-based titles is to provide an incentive for people to play in which they can't "lose ground", like they can with their rating. These have been introduced more recently and many players are not even aware of them.


How to view Arena Chess analysis in a chess program?

This is a log file and can't be parsed. You can view the results in the GUI after the analysis has finished; then you can save the game as PGN (so that it can be parsed by Arena). You can do this by clicking PGN → Save current game in PGN format.


Where is London Chess Classic Pool B's webpage?

Here's how you can find the tournament results:

Link = Chess Results page

Use ctrl + F to locate Tournament selection

You'll then notice all the sections:

Super Rapidplay
FIDE Open
Weekend Open
Weekend U2000
Weekend U1800
Weekend U120
Weekday U2000
Weekday U135
English Junior Rapidplay

Hope this helps.


You can get a count of how many of a particular ECO code (or a particular range of codes) is in the database.

In the Game List, select Change Filter (magnifying glass icon), then Search by Header (binoculars icon). In the dialog box that pops up, there are two fields for ECO code, allowing you to choose a start and end. For example, enter B00 and B99 if you want to count all the B codes. Then click the Search button. The Game List will now show the count of games in the database that match the filter.


After axb4 the a2-pawn is a fixed weakness that can easily be further attacked with Ra8. Defending this pawn will force whites heavy pieces into passive positions.

Taking with the queen or the rook on b4 will allow Rb1 with a rook exchange. Even if this rook exchange happens on b4 and therefore creates the same pawn structure as after an immediate axb4, the defence of a weak a-pawn will be much easier without the rooks. In fact white might be able to exchange the a-pawn for the b-pawn relatively quickly.


How can I frequently practice openings that are more than 1 or 2 moves long?

This is where you have to understand the opening, not just play memorized lines.  If your opponent strays too far from the most popular lines, he's probably made an error.  It's up to you to understand the opening enough to punish him for it.

So you can't force him to play the line but you can make him wish he did.


World Computer Chess Championship: Why don't they run all computers on the same hardware?

I think an historical look at that competition helps make the fact that each engine played on its own distinct hardware setup seem more reasonable. Don't think of it as merely an engine (software) competition, because it wasn't. Instead, think of it as a competition to determine the strongest chess-playing machine (hardware and software combined). And really this isn't so strange, especially given that this series of events dates back to an era when engines themselves were significantly weaker, computing power was more limited, and much less was known than today about how best to apply either hardware or software resources to the problem of computer chess.

Part of the challenge was of course just crafting better engines, regardless of hardware, but doing so in ways that took appropriate advantage of whatever particular hardware one could get a hold of was a significant part of the problem as well. Also (and this isn't a trivial point), these competitions in earlier days were as much (if perhaps not more) a way for hardware folks to show off as it was for engine developers. Consider two-time world champion Cray Blitz (1983, 1986). Its success wasn't just a feather in the cap of Bob Hyatt et al. for their ability to design a strong engine, but also a source of advertising for Cray Research's supercomputer and its ability to outstrip others at handling the calculating complexities of chess.

While I'm at it, for a more obvious example of how hardware was long just as prominent and distinguishing a part of the equation in computer chess, we can think back to Kasparov's 1996-7 matches against Deep(er) Blue, which wouldn't have happened at all (think sponsorship and such) if IBM wasn't eager to test and show off its hardware.

All that said, there is currently a well-known competition that offers what you want to see, which is a hardware-neutral comparison that's specifically designed to determine the strongest engine: Martin Thoresen's TCEC, which e.g. ChessBomb broadcasts when it gets played.


What counts has "having enough material to mate"?

From FIDE Laws of Chess, article 5.2b:

The  game  is  drawn  when  a  position  has  arisen  in  which  neither  player  can  checkmate the opponent’s king with any series of legal moves. The game is said to end  in  a  ‘dead  position’.  This  immediately  ends  the  game,  provided  that  the  move  producing the position was legal. (See Article 9.6).

In your first example, as soon as White plays Qh2+, the statement "a  position  has  arisen  in  which  neither  player  can  checkmate the opponent’s king with any series of legal moves" becomes true. As the rule says, this immediately ends the game with a draw. This happened on White's move and it immediately ends the game, so there is no time for Black's flag to fall.
The same happens in your second example. As soon as a dead position arises, it is a draw.
The position does not need to be dead for a fallen flag to result in a draw. Article 6.9 says:

Except  where  one  of  the  Articles:  5.1.a,  5.1.b,  5.2.a,  5.2.b,  5.2.c  applies,  if  a  player  does  not  complete  the  prescribed  number  of  moves  in  the  allotted  time,  the  game  is  lost  by  the player. However, the game is drawn, if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves.

So if Black's flag falls and there is no legal sequence of moves that results in Black's king being checkmated, it is a draw. For example, if Black has an extra queen in your first example, and Black's flag falls after this move
[FEN "8/8/8/5q2/8/8/Q7/K6k w - - 0 1"]

1. Qh2+

then it is still a draw, because there is no legal sequence of moves can result in Black's king being checkmated.


That is the Slav, but the problem for black in many of these lines, and specifically immediately, is that if 3...Bf5, then 4.cd cd 5.Qb3 forces you to sacrifice d5 or b7 since 5...b6 just loses.

         [FEN ""]

         1.d4 d5 2.c4 c6 3.Nf3 Bf5 4.cxd5 cxd5 5.Qb3! b6? 6.e4! (6.Nc3) Bxe4 (6...dxe4 7.Ne5+-) 7.Ne5 a6 8.Ba6! Ra6 9.Qb5 Nd7 10.Nd7! Qd7 (10...Ra5?? 11.Nf6++#) 11.Qxa6+-

This is just one example, and white can also play it more quietly with 6.Nc3 instead of 6.e4, but no matter how you do it, it is either the loss of a pawn with insufficient compensation, or worse, death on the light squares.

Lastly, you can try to postpone Bf5, but the same basic ideas are still strong later, or you lose a tempo with a6 putting you two tempi down on the same white opening. Basically, the answer is "no", the position cannot withstand the attempt to bring the B out early there.

P.S. I just looked at your picture again, and noticed the computer eval listed, and that +.73 is modest. It will probably grow after just a few moves.


Android Stockfish communication works differently than on PC?

I'm not sure what exactly happened, but looking through the source code, it appears your first token (setoption) is corrupted or not read properly.

Have you modified the code yourself? If so, please revert all your changes.
Please double and triple check the source code where you compile Stockfish.

  As on the very initialisation it doesn't work for me.

You don't need to initialise anything to make SF work. The common uci is absolutely useless (look in the source code to convince yourself). There is nothing you should need to do to initalize the engine.

I believe the problem was in how you compiled the engine. There's not enough information here for me to give you a complete answer.


I have no idea why @Maxwell86 was downvoted. He is correct that Blacks pawns look impressive but it is not easy to see what to do with them.
The pawns are strong if they restrict Whites pieces, or if they are mobile enough to generate threats. Neither is the case here. I would regard 16..e4 as a positional blunder, because it fixes the pawn structure, and allows White to form a plan around it. This might be along the lines of Bc2-Bb3 (hold that QP), f2-f4(giving Black a protected passed pawn, but it isnt going anywhere, and White prevents Black from connecting up his Pawns with an eventual ..f4), Na3-c2-e3 (A perfect square, blockading and influencing both wings), Ra1-b1 or Qd1-d2 (protect the b-Pawn) then in due course c2-c4, Bb3-a4, b2-b4, lauching a Pawn avalanche on the Q-side.

Yes, of course Black gets to move also, but I dont see anything like this plan of campaign. White seems to me to have a big advantage because his Pawns are (or will become) mobile and Blacks will not. Whites strategy in this sort of position is always to advance on the Q-side, while Black usually looks for counterplay on the K-side, but this will not be easy with his pawns blockaded. They hardly restrict White from doing what he wishes, and they cant generate threats. It does take time for White to do everything but Blacks play is even slower. White has only one potential weakness (on g2, which the N already protects. Black will try things like Bg7-h6, Rf8-g8, Qd8-f6-g6, Ne7-g6-h4, against which White has Rf1-f2, Qd1-d2.

There is still a game ahead, but it will be the kind of game where each player forms a plan and tries to achieve their own while frustrating the oponent. My money is on White.


If you have a premium membership on ChessTempo, you can create problem sets with spaced repetition, which is one of the advanced options under problem search. If you select this option, the site will show you both new puzzles and puzzles you've already solved. You'll see puzzles you've gotten wrong more often, and if you get a puzzle right a few times, you won't see it as much.

Lucas Chess, which is a desktop program and free to download, also includes sets of tactics puzzles for training using spaced repetition.


Second Troitzky line, where knight and pawn could be located?

This has been already solved by Helmut Conrady, his elegant 15-page solution is available here.
It is filled with diagrams and examples as you wanted.
Let me know if you have any questions regarding the diagrams or explanations given.
EDIT: In reply to the edited version of the question and the three positions added:
For the position to be winnable under 50 moves, there are two simple conditions:

Either the black pawn is blocked by the knight on the 5th ranked
Or the pawn is blocked on either b6/b7 squares or on g6/g7 squares.

This means:

First position Winning for white in 50 moves because the pawn on c6 isn't advanced enough and is already blockaded, so no hope for black.
Second position Draw because white cannot win it under the 50 moves limit, as no matter what he tries in the current position, the pawn will get the chance to go past the 5th rank. White isn't in time to block the pawn, two examples:

First:
[Title "pawn will advance to 4th"]
[StartFlipped "0"]
[FEN "8/8/8/1N2pk2/1N6/8/8/4K3 w - - 0 1"]

1.Nd6+ Kf4 2.Nd5+ Kf3 3.Nf5 e4

Second:
[Title "pawn will advance to 4th"]
[StartFlipped "0"]
[FEN "8/8/8/1N2pk2/1N6/8/8/4K3 w - - 0 1"]

1.Nd6+ Ke6 2.Ne4 Kf5 3.Ng3+ Kf4 4.Kf2 e4

Third position: Draw: easy enough to see that white can't stop the immediate advance of the pawn past the 5th, so white cannot win under 50 moves.

In order to conclude, although if one of the conditions is fulfilled white will have a theoretical win under 50 moves, but that is only possible if no tempo is lost usually, so techniques like triangulation are continuously applied, as shown in the examples of the link.


What chess books should a Class A player read to reach Expert Class?

I'll start with a few tips and ideas.  None of them are original, but all of them have some value and bear repeating.

(1)  If you have the opportunity to play in tournaments where there are stronger players, this is the best way to improve.  The hard lessons you learn from your tournament games are ones you remember best. Moreover, every mistake you make in a tournament game is showing you a gap (a poker player might say a "leak") in your play. It is no coincidence that all really strong players played hundreds (if not thousands) of serious games before they got really good.

(2)  Learn to sit on your hands.  Not literally, of course, although you could try it if you are really impulsive.  Many players make mistakes they could avoid if they just slowed down a bit, sat on their hands, and thought a little instead of moving quickly.  When I started slowing down and making myself take a little time and think about every move, even the obvious ones, I made a big step forward.

(3)  Learn to fight hard through the entire game.  Don't relax until the game is over.  When you have a won position or an almost-won position, this is when your opponent is often at his most desperate and dangerous, and you should be very careful.  Chess is a game where you can spoil everything with a moment's inattention.  Learning to win won positions in an absolutely relentless fashion without giving your opponent the slightest chance is a very important skill.  Learning to create as many practical difficulties as possible for your opponent when you have a bad or lost position is also very important.  Never stop fighting until the game is over.

(4)  Do lots of puzzles.  Tactics puzzles, positional puzzles, endgame puzzles, it doesn't matter much which. They will develop your ability to solve problems over the board.  People often read through game collections, middlegame manuals, and the like on autopilot without doing a lot of thinking for themselves, and then expect to improve.  But abstract ideas are practically useless in chess. Knowing that the bishop pair is usually an advantage is nice, but does you no good at all unless you have some concrete idea about how to exploit this advantage, and can apply this idea in practice.  You need concrete understanding, and to get it you must be thinking and calculating for yourself all the time.  The more you think for yourself, the better you get at it.  Puzzles are one way of forcing you to think for yourself.  Solitaire chess is another.  I am a big fan of solitaire chess (any at least lightly annotated game collection will do), as it presents you with problems to solve which cover all aspects of the game.

(5)  My last idea is rather murky, but nonetheless very real.  The single characteristic shared by all strong chess players I have known is that they have a strong desire to win: they are highly invested psychologically in the outcome of every game.  They really hate to lose, and they really love to win.  As a result, when they sit down at the board they are highly motivated, they have a lot of fighting spirit, and they are hard to kill.  Anything you can do to increase your motivation (find a rival, set a serious goal, play on a chess team, etc.) is a plus.  In my experience, people who are not highly motivated usually don't get very strong, no matter how talented.

I am a little hesitant to recommend specific books: different people react well to different types of material, and honestly I am not sure what "Class A" means.  There is quite a big difference between an 1800 elo player and a 1999 elo player.

However, I would primarily recommend puzzle books for anyone below about 2100 elo.  Any one of the modern "1001 tactical problems" type books would be good (e.g., Zenon Franco's "The Giant Chess Puzzle Book," Richard Palliser's "The Complete Chess Workout," Igor Sukhin's "Chess Gems," etc.).  An endgame puzzle book rather than an endgame manual (e.g., John Hall's "Endgame Challenge," Bernd Rosen's "Chess Endgame Training," or the like).  Maybe a book with some positional/strategical puzzles as well (something like Johan Hellsten's "Mastering Chess Strategy" would be good, there are probably others).

Maybe add an annotated game collection from one of your favorite players (like Tal or Fischer or Karpov or Kasparov or Anand), or an instructive game collection (like John Nunn's "Understanding Chess Move by Move," or "The Mammoth Book of the World's Greatest Chess Games").  Actually, it doesn't matter so much which book you choose as how you use it.  If you really grapple with the material and try to master it, if you constantly set yourself problems and try to solve them, any decent book can take you a step forward.

I am not going to address openings, as most players below 2200 elo study openings way more than they should.  Just find some solid openings that you like and stick with them, so that you build up some experience in the lines that you play. If you have a problem with a particular line, look up the position in the database and find out what stronger players are playing in that position.

But mostly, a serious approach, motivating yourself to fight hard through the entire game, and a lot of tournament games are the main things.


What are the ideas behind the 4.Qxd4 variation of Philidor's Defense?

The principle is to not bring out the queen too early when it can be easily attacked.  In this situation there's no easy way for black to attack the queen on d4, so it's not too early.  So instead of being a weakness, the queen in a central square is a huge strength.
A very similar phenomenon happens in the following line of the Scotch game where white develops the queen early and gets a +.6 edge and 43%/21% winrate on lichess.
 [FEN ""]
 1. e4 e5 2.Nf3 Nc6, 3.d4 exd4, 4. Nxd4 Nxd4 5.Qxd4


Should a beginner move from fundamentals to opening theory?

Moving from fundamentals to memorization of openings is probably not recommended. I would instead recommend learning the fundamentals of openings (controlling the center, developing minor pieces, don't bring out the queen too early (usually), pawn structure), and then, as you say in your comment, focusing on tactics practice.

If your goal is to play fast games, then studying openings is certainly going to help you increase the speed out of the gates.

If your goal is to improve your slow game, which is probably a good idea for most beginners: my recommendation is to consider each opening move as carefully as you would a move later in the game. Many openings are as tactically tricky as the middle game, so it pays to be careful.

Just my opinion. Obviously, there is a point where learning some openings will be helpful.


What is a good plan for Black when White surrenders the center?

In positions like this (while the a1 rook is undefended), a typical plan  is to play immediately 1...b6 and reply to 2 b4 with 2...a5, the idea being that white cannot defend the b4 pawn with a3.

In order to analyze the consequences of this plan, I'd check the following:

bxc5, dxc5 would give black's bishop the long diagonal and should be preferable for black
cxb6 axb6 (or cxb6) does not seem so clear to me, because the light squares on the queenside get weak. Assessment might depend on whether black can take advantage of the half-open a file and/or can put his queenside pieces to good squares without giving white too much play on the light squares.

...b6 2. b4 a5 3. b5 Does not look attractive for black

So it seems that black does not get anywhere on the queenside, which leaves the pawn break with e5 as the most reasonable alternative. The idea would be to either open the long  diagonal for the bishop (if white captures on e5) or to create a weak pawn on d4 (if black captures exd4, exd4).

There is not much white can do to prevent black from playing e5 sooner or later. The next white moves are pretty much predictable (develop pieces, castle, push pawns on queenside...). The question is how black wants to prepare e5.

... a5 is probably a good idea because it hinders white's natural plan of pushing the queenside pawns

c6 vs Nc6: the pawn on c6 would protect d5 which could be important after white captures dxe5; The knight on c6 looks a bit unnatural, particularly if white manages to create a pawn storm. On the other hand from c6 a knight could put pressure on the d4 pawn.
Bg4: with all white pawns on dark squares, this bishop could be strong. You might not want to exchange it too soon.
Re8: probably a good square for the rook

Taking into account all this and potential tactics such as white sacrificing a pawn on c6 (if black plays Nbd7), etc, I believe the best options are:

Re8, Nc6, e5
Re8, c6, Nbd7, e5
c6, Nfd7, e5 (but black might delay his development too much here)

ALl of these could be combined with Bg4 depending on how much you value bishops vs knights. Personally I'd go with the Re8, c6, Nbd7, e5 plan


Official rules for castling in Chess960? (Is there a loophole?)

Hi thanks for your questions Remellion. I have a better answer for Q2 than Q1, but bottom line there is no loophole in the FIDE Laws.

(1) I don't know of and can't locate any other official source of Chess960 rules other than FIDE rules.

(2) There is a second place in the FIDE rules where we are told how naughty it is to leave a king in check:

  FIDE Law 1.4.1 Leaving one’s own king under attack, exposing one’s own king to attack and also ’capturing’ the opponent’s king is not allowed.

This would apply independently of the number of pieces involved in the castling. So there is no loophole.


Normal draw positions in the endgame KQPKQ with a bishop-pawn?

According to the tablebase here, this position is a draw. Of course, with the open position, Black threatens perpetual check with any free move.

[FEN "3k1q2/8/8/8/8/8/5P2/3KQ3 w - - 0 1"]


Openings that tempt opponents to overextend?

Norwegian Defense.
Perhaps THE best scoring defense on Lichess (White scores below 45% on 2000+ rating), even though it is positionally dubious and does not set any tactical traps.
[FEN ""]

1.e4 g6 2.d4 Nf6 3. e5 (3. Nc3 d5 4. e5 Ne4 5. Nxe4 dxe4) Nh5


What are the general principles for playing hypermodern against hypermodern?

Good question. I personally have tried as White to avoid advancing my center pawns and fiancheto one or both my Bishops, and control rather than occupy the center. For example I opened 1.b3. My experience tells me that Black can in fact set up a pawn center and have it solidly reinforced, thus equalizing. You get a center and now you have to be careful and watchful to not miss white's breaks (or even sacrifices) blowing up that center and leaving you with weak pawns.

Choose some key squares that you want to completely control and center your game on that. For instance, let's say you want to have a pawn d5 and you focus on hindering the e4 square, not allowing White to advance his/her pawn to e4 easily. Then you'd like a knight on f6 and maybe a bishop on f5 (or g6). You may also put a rook on e-file. Similarly, you may put a pawn on e5 and control the d4 square with a knight on c6, a well-placed dark squared bishop, etc.

It is usually impossible in practice to have two pawns in the center (say both e5 and d5) and yet protect them completely. So, do not get greedy for central pushes, having one pawn that is solid is better than having two that are shaky.

If you take into account whites c-d-e-f pawn pushes and subsequent exchanges and/or closings of the center, you should be fine. Usually a central control is a big advantage, and your opponent has to do something to free their pieces. If White does not want to advance his/her e and d pawns more than 1 square, how are they going to launch any serious initiative.

So, in summary, if Whit does not want the center, go ahead and occupy it yourself. Build up a solid center with pawns protecting pawns and pieces boosting them. You'll enjoy more space behind your pawns than your opponent will behind theirs!


Do tactics regularly (possibly every day). Below 2000 rating is probably the best thing you can do, especially if you have a weak point there.

Ideally you want to practice for ~20-60 minutes (depending on how committed you want to be) on problems that do NOT give away the theme of the tactic involved (e.g. "exchange sacrifice", "overload", etc).

Another thing you can do is to review your games, and if you lose due to tactics try and figure out which was the best response to parry that blow. In any case reviewing your own games is the key to improve (first review them on your own, and once you're finished go through them with an engine).

Finally, I think you might want to watch other people playing, especially ranked 200-400 higher than you, and then review those games as well. I find it very useful because I usually understand the reasoning behind moves I didn't think about during my own games.


Which gambits get good results if they're accepted, but lead to poor results for the gambiteer if they're declined?

One example is the so-called Calabrian Countergambit: 1.e4 e5 2.Bc4 f5. After 3.exf5 Nf6, black seems to be fine. However, white should ignore the gambit and play a developing move: 3.d4 (Bologan-Bednarek), 3.d3, 3.Nf3 or 3.Nc3.

      [StartPly "4"]

      [FEN ""]
      1.e4 e5 2.Bc4 f5 3.exf5 (3.d4)(3.d3)(3.Nf3)(3.Nc3) Nf6

Another example is a line in the exchange variation of the Ruy Lopez: 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6 dxc6 5.0-0 Bg4 6.h3 h5. Accepting the sacrifice with 7.hxg4 is clearly too dangerous as it opens the h-file for the black rook. White is probably slightly better if he declines the sacrifice with 7.d3 (Naiditsch-Mons).

      [StartPly "12"]

      [FEN ""]
      1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6 dxc6 5.O-O Bg4 6.h3 h5 7.hxg4 (7.d3) hxg4


What is the Bronstein (delay) equivalent of Fischer time control of game in 90 plus 30 second increment for FIDE rating?

That players will typically not use the full extent of the delay is not relevant. The minimum time requirement refers to the least upper bound of the possible amounts of time the players could theoretically take. Thus, G/90 d30 satisfies the requirement, although it is a very uncommon control.


This entire endgame has been analyzed thoroughly on ChessPub. It seems that member Wes was right -> ...g5 is the main move. This was confirmed with a lengthy analysis at ChessCafe -> see the first position on the page ( there are some other games analyzed after the analysis of this position finishes ). I am sorry for posting links but the analysis is huge!

Good luck and hopefully this answered your question!

Best regards!


Is there a good or a proper age to play chess?

Like learning to speak the appropiate age will vary from child to child.

I think 3 and older (My 10 year old brother taught me when I was 3). Children are naturally curious about any activity their parents/siblings do.  Just play chess in front of them and if they show interest show them how each of the pieces move.  At very young ages you will need to be extremely patient as some rules such as the knight movement and castling are quite difficult for young children to understand.


Per Wikipedia:

Castling was added to European chess in the 14th or 15th century and did not develop into its present form until the 17th century. The Asian versions of chess do not have such a move.

The King seems to have always moved the same as at the present, except that the game used to be played until he was actually captured. Because of the King's vulnerability due to the Queen's enormous scope and power, several methods of "castling" were tried before the 16th century.

One method was to allow the King to move two or three squares on its initial move.
Another method was to allow the King to move directly to g2.
The present method of castling was documented as early as Ruy López's 1561 work Libro de la invención liberal y arte del juego del Axedrez.


Which was the first televised/video-recorded WCC match?

From a report by Harry Golombek on the seventh game of the Botvinnik v Smyslov world championship match in Moscow on 30 March 1954:

Television made its first appearance in the history of world chess championship matches during the course of this game, which was televised from 8 till 8.30 p.m.
Source: BCM, May 1954, page 141.

The 24-game match had 14 decisive games, 12 of the first 16, including a streak of 8 decisive results in a row! All the games were full of fight, and many of the games were of theoretical significance.


Book recommendation for chess engine building

To my knowledge there is no book on chess engine programming because there is no market.
People study the source code simply by reading it. If you have any question, please join Stockfish/LC0 discord. It worked well for me, I just ask online anything I don't understand.
I would suggest the following on learning. Many more I may have missed.

https://www.chessprogramming.org/Main_Page
https://www.talkchess.com
https://lib.vsu.by/jspui/handle/123456789/20821 (Deep learning for chess ai)
Stockfish/LC0 discoards
https://groups.google.com/forum/#!forum/fishcooking


Why does AlphaZero evaluate on the order of 1000 times less moves than Stockfish?

Very simple. Running a large neural network with floating numbers can’t be quicker than running a simple C++ function on integers.

AI machine learning is not new to chess. There were serious attempts before Google established. Unfortunately, nobody had the determination, skills and resources to do a good job. Nobody wanted to invest money. Before Google's chess journey, the chess engine community believed:

  AI chess will not beat classical programming because neural networks
  (or other models) run much slower.


The first example is invalid in PGN, please don't do that. Your second example is also invalid. We don't put comment to the same line as the header.


Black is pretty well busted.  His minor pieces are inferior to White's. His Queen has few squares and will end up on f7, f8, or h6. He has not yet castled.  Plus he's down a pawn and has an isolated e-pawn whose weakness is accentuated by the uncastled King.

White has a grasp on the center, good pawns, a castled King, and a Rook on the best file. I don't care for the fianchetto'd g-pawn with the light-squared Black Bishop and Queen on the board, but if Black can't exploit it then it does not matter.

Stockfish isn't very excited about Black's chances and believes the game to be decisively won by White:

[FEN "r3k2r/pppbn2p/4p1p1/8/3PNq2/2PB2P1/PP3P1P/R2QR1K1 b q - 2 2"]

2... Qf7 3.Qb3 O-O-O 4.Ng5 Qf8 5.Nxe6 Bxe6 6.Rxe6 Nc6 7.Ba6 bxa6 8.Rxc6 Rd6 9.Qc4 Rxc6 10.Qxc6 Qe8 11.Qxa6+ Kb8 12.Rd1 Rf8 13.d5 Qe7 14.Qb5+ Kc8 15.Qc4 Qd6 16.Kg2 h6 17.Qe2 Kd8 18.Qe3 Qb6 19.Re1 Qxe3

With a score of +4.2.  None of those moves look too hard to find, and I'd wager White can find good moves easier than Black.


Is it legal to move a piece if your opponent has not hit the clock?

Yes, it is.

Let's take a closer look: Article 1.1 of the FIDE rules states:

  A player is said to ‘have the move’ when his opponent’s move has been
  ‘made’.

Article 4 clarifies how a move is supposed to be made. Specifically:

  When, as a legal move or part of a legal move, a piece has been
  released on a square, it cannot be moved to another square on this
  move.

At that point a move has been "made".

Note, however, the provision in article 6.2:

  A player must be allowed to stop his clock after making his move, even
  after the opponent has made his next move.

Even if your opponent already moved, you still have the right to press your clock.


Who wins in the game "knight" if both players play optimal?

In my answer to the same question over on math.stackexchange, I discussed general m by n boards. Here I will just give a winning strategy for Player 2 on the ordinary 8 by 8 chessboard. It's based on the following pairing of squares:

a1c2, b1d2, c1a2, d1b2, e1g2, f1h2, g1e2, h1f2,
a3c4, b3d4, c3a4, d3b4, e3g4, f3h4, g3e4, h3f4,
a5c6, b5d6, c5a6, d5b6, e5g6, f5h6, g5e6, h5f6,
a7c8, b7d8, c7a8, d7b8, e7g8, f7h8, g7e8, h7f8.

That is, square a1 is paired with square c2, b1 is paired with d2, and so on. Note that the 64 squares are partitioned into nonoverlapping pairs, and each set of paired squares are a knight's move apart. The winning strategy for Player 2 is: WHEREVER PLAYER 1 PUTS THE KNIGHT, MOVE IT TO THE OTHER SQUARE IN THE SAME PAIR. For instance, if Player 1 starts the game by dropping the knight on e8, Player 2 replies by playing Ng7. If Player 1 now plays Ne6, Player 2 plays Ng5, and so on. Here is a sample game, with Player 1 making random moves, and Player 2 following the winning strategy described above:

Ne8 Ng7 2. Ne6 Ng5 3. Nf3 Nh4 4. Nf5 Nh6 5. Nf7 Nh8 6. Ng6 Ne5 7. Nc6 Na5 8. Nb3 Nd4 9. Ne2 Ng1 10. Nh3 Nf4 11. Nh5 Nf6 12. Ng4 Ne3 13. Nc5 Na3 14. Nb1 Nd2 15. Nf1 Nh2 and Player 2 wins.

P.S. Of course the strategy still works if White is allowed to move the knight to any square not already visited, and only Black is limited to making knight moves.


What does it mean for a country to be a FIDE "Affiliated Organization" instead of a FIDE Member?

It doesn't appear that this will have a large impact on the players themselves. The organization can organize events and gets nonvoting representation in FIDE.
According to the FIDE Charter:

14.1 The General Assembly, following an advisory opinion of the Council, can be admitted as Affiliated Organisations:
a) organisations grouping Member Federations;
b) associations or organisations which represent some regions or transnational territories;
c) associations or other organisations representing people with a common ground or with same interests on some specific chess activities.
14.2 Affiliated Organisations have the right to take part in FIDE Congresses and in the General Assembly, without voting.
14.3 Affiliated Organisations can organise and participate in some specific FIDE competitions or events, according with FIDE rules and regulations.
14.4 Affiliated Organisations can be authorised to organise events under the auspices of FIDE.
14.5 Affiliated Organisations can be temporarily suspended or permanently expelled by the General Assembly, for just cause.

As for why the situation with other UK protectorates is what it is, I suspect that these rules have something to do with it (emphasis mine):

9.2 Only one Federation for each country can be affiliated to FIDE as a Member. This rule shall not apply to Federations that were accepted as FIDE Members before the date of this Charter entering into force.

9.4 For new members, the country of the federation must be a country recognised by the United Nations and the International Olympic Committee(IOC).


First, I assume that you mean 15.h4 (not h5).

If so, the main reason is that a lot of master-level chess is restricting your opponent's pieces, or in this case, even driving them back. The Ng6 has no good squares, and h5 driving to to a worse square is threatened. If 15...Be7; 16.h5 Nf8, and not only has the Ng6 been driven back, and still has no good squares, but now the Rh8 is doing nothing, and white may get a direct attack against the Ke8, which is stuck in the middle. A specific line is 15.h4 Be7; 16.h5 Nf8; 17.Rg1 g6; 18.Ng5 with the threat of Qf3 hitting f7 and the Ra8. If Bg5 then the dark squares are critically weak.

That leaves only 15.h4 h5, but then 16.Rg1 Bb7; 17.Bd3 already has critical threats since black's king is not going to have anywhere safe to hide, and if the N retreats, we are back to similar ideas as above (Nf7 and the Rh8 problems).

As far as how you know when to do this, there is no hard-and-fast rule, but in this case, you have to realize that the pieces can be restricted, which is pure analytical work.

P.S. Let me also reference chapter 7 from the book "Find the Right Plan with Anatoly Karpov" (beware of this book in that the title in Russian is "Plan and Evaluation", and the book really is not really much about planning). The title of chapter 7 is: "The most important law of chess". That "law" is: "Restricting the mobility of your opponent’s pieces (and in association with this: domination by your own) – is the most important law of chess."

That is the primary thing that is going on with 15.h4. In conjunction with that is the weak K, and the fact that the Ke8, in essence, divides the board k-side and q-side, and prevents pieces from helping out the other side.


Is it preferable to pass a FEN notation or list of moves to a chess engine?

It is preferable to pass a PGN because FEN is just a position with no move,  but a PGN is the whole game with moves.


How many materially equal positions are there?

What follows is basically a partial answer that is heavy on explanation, plus a pointer for using it to obtain a fuller answer if so desired.

Suppose we start with a blank 64-square chessboard and ask how many different positions we can make by placing down just 2 white knights. A quick answer is that it is 64*63 = 4032 positions, because we can place the first knight on any of 64 squares, and for each of those choices there are 63 remaining choices for the other knight. But this overcounts a bit. Specifically, that number double-counts every possibility, the reason being that our white knights are indistinguishable in terms of a chess position. What I mean is this: the counting scheme above treats (A) placing Knight1 at a1 and then Knight2 at a2, and (B) placing Knight1 at a2 and then Knight2 at a1, as two different chess positions. But they aren't: each has a white knight at a1 and at a2; they are the same chess position, as white knights don't come with individual labels. So the real answer should be (64*63)/2 = 2016 positions.

If we were instead placing 8 white pawns on an empty 64-square board, the number of possibilities is

(64*63*62*61*60*59*58*57) / 8! = 4,426,165,368

This is just like the previous example, where the numerator naively counts the ways to place the 8 pawns, and the 8! of the denominator accounts for the fact that our white pawns are indistinguishable from one another in a position (and there are 8! ways to order the 8 pawns). Note too that the numerator can be written more succinctly as 64! / 56!, so a snappier way to give the number is as

64! / (56! * 8!)

OK, so what about Shannon's paper itself? The estimate of the number of chess positions given there is that it is "of the general order of"

64! / (32! * (8!)^2 * (2!)^6) = 4.63E+42

From the examples above, we know what this is counting. The 64! / 32! naively counts the number of ways to drop 32 pieces onto the 64 squares of the chessboard. Then we divide by 8! twice to ignore the order of the white pawns and the black pawns. Finally, we divide by 2! = 2 a total of 6 times, to account for the white/black knights, bishops and rooks. So this 4.63E+42 is a rough estimate of the number of 32-piece positions, all of which have even material of course. (Note that we are totally ignoring legality, e.g. we can have pawns on the first rank, both kings in check, and so on; for an interesting thread on the proportion of positions that are actually legal, see this MathOverflow post. We are also ignoring promotions by saying that the original 32-piece set is all we get.)

A similar "Shannon estimate" for the number of 31-piece positions is given by

  1.40E+41 = 64! / (33! * (8!)^2 * (2^6))      remove white Q
  2.81E+41 = 64! / (33! * (8!)^2 * (2^5))      remove a white R
  2.81E+41 = 64! / (33! * (8!)^2 * (2^5))      remove a white B
  2.81E+41 = 64! / (33! * (8!)^2 * (2^5))      remove a white N
+ 1.12E+42 = 64! / (33! * 8! * 7! * (2^6))     remove a white P
----------
  2.11E+42
* 2           to count those positions removing a single black piece
----------
  4.21E+42

Note the huge drop in the number of positions: there are 4.21E+41 more 32-piece positions than there are 31-piece positions. The numbers will continue to drop dramatically, and in fact the proportion of 32-piece positions among all possible positions will be fairly sizable (hence so too will the number of even-material positions).

It wouldn't be too difficult for someone to write a program that produces these Shannon estimates for all numbers of pieces (one would just need to make sure to account for all combinations of a given number of pieces), and we could keep track of all those combinations that have equal material as we go. At the end we would have the Shannon estimate for all possible positions (though the 32-piece number already gives a rough sense of the total, as Shannon notes, because of the quick drop in positions as we drop pieces), as well as a count/proportion of how many of those (pseudo-legal) positions have equal material.


I would like to know if this game is winnable for black?

Black has an overwhelming advantage and should win easily. Being up by a whole piece is a huge advantage that basically can't be overcome by purely positional considerations.

The most straightforward way for Black to win is to try to trade pieces and end up in an endgame where he has one piece to White's zero; a win at that point would be trivial.

He could also try for a kingside attack, since White's light squares are very weak.


The only way I know of playing bughouse using XBoard/Winboard is to play via FICS, see e.g. https://github.com/ianfab/Fairy-Stockfish/wiki/Setting-up-Fairy-Stockfish-on-FICS#bughouse (it works very similar for other bughouse engines), i.e., it does not work offline. You would just use four FICS guest accounts whereof three are your engine instances, and create two bughouse teams from them. I tried this several times already and for me it works fine, although of course it is not very convenient to set up, but once set up it works smoothly.


How would you evaluate this king and pawn endgame for white, and what's the best book to study King and pawn endgames?

There were a lot of inaccuracies by both players, I don't think you were ever losing, but you certainly threw away the win occasionally. I think three concepts might be helpful to you:

A protected passed pawn is very strong in a pawn endgame because it forces the enemy king to keep an eye on it at all times. Therefore allowing 46…e4 was a big mistake that turned an easy win into a draw. Instead take on e5, play h5 and h6 and then round up the black pawns.
Two connected passers are even stronger, because basically that's a dynamic duo of protected passers: The enemy king can never take the more backward one, because the other one will queen. And whenever possible, they will advance. See again move 46. If you take on e5 and black retakes with his king, you can fearlessly advance because as soon as the black king returns to g6 to attack the h6-pawn, you just protect it with g5.
The king is often curiously helpless against two pawns that aren't even connected and just one square apart: That's why 50.c4 was another big mistake. If black takes this pawn, there is no way for you to get at either the e- or the c-pawn. So 50…dxc4 51.Ke3 c3 and you cannot take on e4 because the c-pawn will queen. (Edit: Dag points out that after dxc4 b5 might still win for white, so maybe it wasn't a mistake, but the concept is still useful. Instead of dxc4, b5 should draw for black.)


As for "both positions seem fine for White": well, Black has a significant material advantage after 5...gxf3, so White has to find some compensation. If you don't have a concrete continuation which demonstrates that compensation, I don't think there's any reason to think the engine evaluation is confused.
In both positions, a sensible continuation is 5... gxf3; 6 Qxf3 Qf6; 7 d3. Now in the original position Black has doubled f-pawns and a bad pawn structure; in particular the pawn on f4 can't be supported effectively; when it falls Black will have two isolated pawns. Black stands better but has some weakness that White can try to exploit. In the position with the pawn moved from f7 to g7, Black could play 7... g5 immediately, or alternatively 7... Bc5+ and then 8... g5. Now Black's structure is more solid and White doesn't have anything like enough to justify the material disadvantage.


Why is the light-squared bishop considered White's best bishop?

The black king, will occupy e8 and g8 (before and after castling, respectively), both of which are white squares.  Also, the weakest point on the black kingside is f7, again a white square.  Because of this, if you are trying to attack the king, the white bishop can often be more valuable.

Perhaps someone else can add some more deeper reasons, but this has been my experience.

Added: Also worth noting, attacks on h7 can often threaten mate, another white square.  Furthermore, just having the bishop on the diagonal attacking f7 would pin the pawn to a castled king.


I have not tried this myself, but there is a forum post on chess.com that has instructions on how to do this in SCID (http://www.chess.com/forum/view/help-support/sorting-a-pgn)

Make an empty scid database
Import your games
Do database maintenance - Sort by date
Export your databse to PGN


Can one mate a lone king with Bishop and two knights without being aided by the attacking king?

Work in progress

You can convince yourself easily, that mate is only possible in a corner of the board. We distinguish four cases:

The corner is the same color as the bishop and the bishop mates
The corner is the same color as the bishop and a knight mates
The corner is the opposite color as the bishop and the bishop mates
The corner is the opposite color as the bishop and a knight mates

For the following analysis we only consider unique positions that are not related by symmetry. Also we don't distinguish between similar positions of a bishop along a diagonal, if the same essential square(s) is covered.

Starting with the first case, bishop same color as the corner and the bishop mates. There are 5 distinct (up to symmetry) mating positions: 1.1a to 1.1e.

Doing a retro-analysis for 1.1a and 1.1b:

White's last move was Bb7+ and the bishop came from c8 or a6.
Black's last move was Ka8 and the king came from b8 or a7. The king was not forced to go to the corner and could have escaped to c7 or b6 instead.

Doing a retro-analysis for 1.1c, 1.1d and 1.1e:

White's last move was Be4+ and the bishop came from somewhere along the b1-h7 diagonal.
Black's last move was Ka8. If the king came from b8 or a7, it could have gone to b7 instead of the corner. If the king came from b7, it could have gone to (among others) c6 instead of the corner.

So in conclusion, it is not possible to force a mate with the bishop in the corner of the bishop's color.

The second case, bishop same color as the corner and the knight mates. There are 2 distinct (up to symmetry) mating positions: 1.2a and 1.2b.

White's last move was Nb6+ and the knight came from a4, c4, d5, d7 or c8.
Black's last move was Ka8. If the king came from b7, it could have captured Kxc6 instead (note that the c6 knight was not protected then).

If the king came from a7 or b8, there is actually a longer series of forced moves leading to mate! Needs further invetstigation.

2. Corner opposite to the bishop's color

2.1 Bishop mates

You easily see that there is not even a theoretical mating position for this case.

2.2 Knight mates

You easily see that there is not even a theoretical mating position for this case. In order to mate, one knight would have to check the king in the corner, say a8, the other knight would have to cover the light square b7 and the bishop would have to cover both a7 and b8 which it cannot.


I worked on a Scala implementation a few months ago, although it was a bit unpolished--I should go back to finish it. I at least got some reasonable results from it.

If you win every game you play, yes, your rating will grow to be quite high even if you play against only low rated players. The probability that you will win every game against such an opponent is probably about what a class A player would achieve (although it probably is a bit inflated due to the relatively high RD, still).

The best way to counter, in my opinion, is to not consider someone with an RD over a certain amount to be a stable rating--i.e. consider it to be "provisional". Also, in order to actually gain a title, at least in USCF, they have a system of norms, where you must perform at a certain level in a tournament of 4 games or more (4 times, I believe), which makes the likelihood of playing against a ~1378 for the whole tournament [four times] very unlikely.

Is your goal to use this for chess? What is your use case?

Update:
FICS handles it by only considering people with an RD of <80 active. (They use Glicko-1, still, I believe.) http://www.freechess.org/Help/ficsfaq.html#Q005.003

And by the way, Glicko-1 uses RD/time decay as well. Glicko-2's main improvement was the "volatility" factor, which allows people with erratic results or stable results to be calculated very slightly differently. I think it's a very minor tweak to Glicko-1 which causes considerable extra calculation--but like you, I was still interested in calculating it. I actually asked Glickman himself for some additional datapoints for testing, but he was too busy to supply them at the time.


is it necessary to learn all these variations that go beyond the
  opening?

I would say no it is not necessary to focus on the opening that much until you are playing chess at a very high level. If you are a beginner the best advice would be to dedicate most of your study time to middlegame tactics and strategy, as well as some basic endgames. Here is a quote of Capablanca on the matter

  I have very often met players who know the openings by heart; that is
  to say, they have learned from some book or other and they think they
  know them very well. And indeed they do know them very well by heart,
  but nothing more. They do not understand the objectives behind the
  openings and therefore do not know what advantage has to be taken of
  them, and it often thus happens that they lose. And they lose because
  they have studied the openings badly without learning them or because
  they have not studied them in depth. It is clear that this can happen
  to anyone, but it is more likely to happen to someone who studies only
  the openings than to someone who dedicates himself to study of the two
  other phases.

The quote is from a lecture you can read online

ps. You will probably also benefit by studying the games of the masters... for example, by using a book as Irving Chernev's Logical Chess... Good luck!


Botvinnik believed in peer review.  He would write up annotations for his games, and publish them hoping for feedback from other players.  He also recommended to his students that they annotate their losses, and also look for mistakes in the games they won.  These elements are all part of his 'scientific' approach.

Fischer always kept the endgame in mind, preferred bishops over knights, grabbed pawns if he thought he could get away with it.  Mikhail Tal would wait until the time control drew near, and then suddenly start to complicate the position, trying to induce his opponent into blundering.  Fischer was much more straightforward, playing the board more than the man, not indulging in psychological ploys as much (at the board anyway).  After the game was over, his opponent would look at Fischer's moves, and think they looked obvious in retrospect.  These are the factors that make his style 'crystal clear.'


The answer is very simple. A 6 year old child does not have an adult brain. It has the very immature, underdeveloped brain of a 6 year old. It has a short attention span and struggles to sit still for 5 minutes let alone spend 5 minutes on just one move.
A few years ago I was chief arbiter for three junior tournaments held at the same time. I got one of the coaches who is also a qualified arbiter to help me. Obviously he wasn't allowed to help his players even in the breaks between rounds.
Instead before every round he stood up and made the same speech basically begging the kids to take more time over their moves. The time control was something like 25+5 and yet most games were over in less than 10 minutes with the players thoughtlessly blitzing out moves.
As he explained to me, kids tend to move too fast in games which are just friendly, relaxed games. But when it is a competition and clocks are involved their brains interpret it as some kind of race and they have even less control of their time management. Adrenaline takes over and calm calculation flies out of the window.


Either is fine. bxc3 gives you a strong chance to push in the center successfully. It leaves a dangling pawn on a2, but by playing bxc3 you should already have resigned this pawn's fate to some sacrifice for a tempo later in the game. Note you can not play 6. d4 right away since black's response will most likely be 5. ... d5 or 5. ... Nf6 putting pressure on the e4 pawn which is awkward to defend for you at this point. You should most likely respond 6. d3 which dashes any hopes you had for a pawn charge to d4. Also, black can exert pressure on the doubled pawn at c3 which is also a bit awkward for you to defend.

I personally would play dxc3. It is less committing. You no longer have to hope to pry open the middle with your pawn majority, and you have no dangling pawn you have to sacrifice eventually. You've opened up strong lines for all three of your white bishop, your dark bishop and your queen. Note this may seem not that important, but keep in mind your opponent just traded one of his bishops for your knight. If you can open up this game, you will have a strong edge on your opponent. Any attack on your e4 pawn can now be refuted, such as 5. ... Nf6 comes in with a strong pin 6. bg5. Also, it no longer looks silly for your white bishop to travel to d3 to defend e4.


Comment/variation with different starting position

You can't do this in PGN, not the way you want it.

There are some tricks that publishers (especially Everyman) use to create their "PGN ebooks":

They split the book over many different PGN games. You'd say "Here I remembered an earlier game that had a similar position; see X vs Y after this game."
A variation that starts at move 1 has to start at move 1: 1.d4 ({Our previous game went} 1.e4 c5) 1... d5
Null moves can be added as --, to show threats and such: 1.e4 e5 2.Qh5 Nc6 3.Bc4 ({With the subtle threat} 3... -- 4.Qxf7#)
You can have several variatiations all starting with the same move, or all with the null move, as poor man's paragraphs.
If all else fails, just leave it as text. People still buy paper books so it can't be that bad...

Note that the variations I had, with a comment starting before the first move of a variation, may be something that not all software supports; I'm not sure. It used to be possible to enter comments like that with older versions of Scid but newer versions make it hard to get to the point where you are still in a variation, but before its first move. I think it's legal PGN though.


What K factor should be used if two players are in different K factor brackets?

K-factor is used for each player individually. So, if one of them got 30 K-factor, his rating will change on the basis of that K-factor, while another player with 10 K-factor, for instance, will get rating on the basis of his own K-factor.

There are Chess Rating Calculators on FIDE's official website. You can have a look: FIDE Rating Change Calculators


Has anyone had positive results using the Ruy Lopez Norwegian variation nightingale gambit?

7...Ke8?? is a blunder for black. Instead, 7...Ke7!? is a much better try with the idea of weathering the attack with moves like ...Nf6 ...d6 and ...Qe8 (not necessarily in that order). Hard to prove that white is winning.


Why do women need less ELO to obtain FIDE titles?

I think WFM Rodrigo is correct when she says that the reasons are statistical and that having fewer female players means having far fewer players at the top.
If you assume that males and females have the same mean and standard deviation (we shall see soon that this assumption is false) and you draw the two normal curves you see that the curve with fewer members (females make up only 15% of FIDE registered players) tails off to zero long before the one with more members.
However WFM Rodrigo also mentions "cultural" reasons. Translated into mathematical terms I think she is suggesting that females have a lower mean (average) FIDE rating than males. This we can check by loading the latest FIDE rating data into a database and doing some SQL queries.
Doing that gives us:
Female
Mean = 1505, standard deviation = 339
Male
Mean = 1675, standard deviation = 346
We see that there is little difference between male and female standard deviation but the mean female ELO is 170 points lower than the mean male ELO. This is half a standard deviation which is a lot. It looks to me that WFM Rodrigo is right about this too.
Comparing these figures with the rating differences between the open (there are no male only titles) titles and the female only titles it looks like FIDE are being generous to the females by a margin of 30 points. Perhaps they rounded the difference up to the nearest hundred?


Is there a tool to automatically download a player's latest ICC games (history) into a pgn file?

Unfortunately, if you want to download them, you have to do them one at a time.  ICC does have a command "mailstored" which allows you to automatically have the games mailed to you in pgn or non-pgn format.  Here is more info on that:

ICC Help: mailstored
Command:  mailstored
Examples:  "mailstored darooha 8" -- This mails game #8 in darooha's history.
           "mailstored darooha POTZY" -- mails the adjourned game.
           "mailstored 5" -- mails game 5 in your current search list.
           "mailstored %5" -- mails game 5 in your personal library.

This command mails you the moves of the game you choose. You can email games from histories, libraries, database (search list), and adjourned games.

To automatically email all the games you play right after you play them, type "set automail 1".

"set mailformat 1" to get the game in PGN notation. "set mailformat 0" to get them in a non-PGN format that also includes the move times. Or "set mailformat 2" to get them in PGN with the clock times (the time remaining after each move) in comments.

There is a limit on the number of games you can "mailstore", due to the load the mailing puts on the ICC CPU. The limit is approximately 50 games in 12 hours. The games you get from "set automail 1" do not count towards the 50. There is no command to mail many games with a single command.

For Dasher and Blitzin, you can have every game you play automatically saved to a PGN file upon completion.

For Dasher:

http://www6.chessclub.com/helpcenter/Dasher/AutoSave.htm

For Blitzin:

Place a mark next to "Log my Games" on your Game menu. This will cause each completed game to be saved to a .pgn file on your hard drive.


What influenced the development of the King's Indian Defense?

In all the Indian Defenses, in general, Black allows White to occupy the centre with his pawns.

Nonetheless, in Nimzo-Indian and Queen's Indian Defense Black has many moves to attack White's pawn centre very early in the game, thus White cannot gain too much space.

King's Indian Defense (and Gruenfeld Defense), on the other side, really do not care that much for the first 4-5 moves of White, so that he can occupy the centre with an "horde" of pawns (see for example the Classical Variation, the Saemisch Variation or the Four Pawns Attack), with a huge advantage of space.

Since hypermodern principles in chess were born only in early 20th century, they were not universally accepted before '40s. And having such a big space disadvantage in the opening was seen with suspect (if not explicitly considered "strategically losing"). That's why, in my opinion, KID had to wait to be considered consistent enough to be played regularly by top players.


Women in Chess - First women-only event.

The First International Ladies' Chess Congress in London, 1897. Games commenced on June 23 and the tournament was finished on July 3. It was organized by the Ladies' Chess Club of London and the Women's Chess Club of New York. The time control was 20 moves per hour, from 1 to 5 pm and 7 to 11 pm. Two games were played per day.

Results (after 19 rounds):

Mary Rudge 18.5
Louisa Matilda Fagan 15.5
Eliza Mary Thorold 14
Harriet J. Worrall 13
Marie Bonnefin 12.5
F. Sterling Barry, Edith Margaret Thomas 11.5
Gertrude Field 11
G. Watson, A. M. Gooding 10.5
E. H. Sidney, Alice E. Hooke 10
Rita Fox 9
Anna Hertzsch 8.5
Eschwege 6
Müller-Härtung 5.5
De la Vigne, Forbes-Sharpe 4
Finn 3.5
Stevenson 1

Referee: Harry Nelson Pillsbury

My sources are

Batgirl: Women Can Play Chess!, 2013, chess.com
Joost van Winsen: The Ladies Made an International Move, 2016, chess archaeology (with many pictures!)


Have you taken a look at lichess.org ? It has a solid web interface, Android/iPhone applications, plenty of chess games/variants, analysis move, there are a few trainings, starting from the basics and ending with pretty advanced stuff, finally there are puzzles taken from the actual chess games, where you have to win the game someone won (or lost) before.


What advantage does black gain from this move?

There is no good way to stop Qg7 mate. Black has to give up their queen.


Are there any cloud engine services solely 'pay per use'?

Lots of them let  you pay zero per use.
Download your own program and you only pay once.


White's c5 in Semi-Slav (or Slav) Defense

This is problem 34 from The Reassess Your Chess Workbook: How to Master Chess Imbalances by IM Silman. The notes are derived from his annotations:

  White has tried many moves here: 9. e4, gaining central space, and 9. b3, preparing to fianchetto the c1-Bishop and also giving White the chance to meet ...dxc4 with bxc4, both make sense. How would you judge the aggressive 9. c5?

[FEN ""]
[StartPly "16"]

1. Nf3 d5 2. d4 Nf6 3. c4 c6 4. Nc3 e6 5. e3 Nbd7 6. Qc2 Bd6 7. Bd3 O-O 8. O-O Qe7 9. c5 Bc7 10. e4 dxe4 11. Nxe4

What does White achieve in the final position?

Better control over e4 and d6
Black's freeing maneuver of b6 and c5 has been stopped
Although d4 is a backward pawn, it cannot be attacked so easily and helps cramp Black

For why c5 is not as popular, Silman offers:

  At one time this move would have been the object of derision; White makes a one-move threat that's easily dealt with and... takes all the pressure off the Black d5-pawn.

In summary, c5 is played to gain space, hence cramping Black.


When I touch two pieces simultaneously, how will the touch move rule
apply?

It will primarily depend on your intention, or rather what onlookers clearly perceive as being your intention.
Here's what the latest FIDE Laws of Chess have to say:

4.1 Each move must be played with one hand only.
4.2.1 Only the player having the move may adjust one or more pieces on their squares, provided that he first expresses his intention (for
example by saying “j’adoube” or “I adjust”).
4.2.2 Any other physical contact with a piece, except for clearly accidental contact, shall be considered to be intent.
4.3 Except as provided in Article 4.2, if the player having the move touches on the chessboard,with the intention of moving or capturing:
4.3.1 one or more of his own pieces, he must move the first piece touched that can be moved
4.3.2 one or more of his opponent’s pieces, he must capture the first piece touched that can be captured
etc.

The firs thing to note is that of you used two hands then that will be punished as an illegal move (article 7.5.4).
If it is clearly accidental then you will be permitted (required) to move the piece that it was clearly your intention to move. An example of this is something which sometimes happens to me when I reach across the board to move a piece on the far side and my forearm brushes and sometimes knocks over the tallest piece on my side of the board, my king.
So, that leaves cases where you deliberately touched two pieces simultaneously with one hand. There are two articles which deal with that in the laws, one more draconian than the other and so far less likely to be invoked.

11.5 It is forbidden to distract or annoy the opponent in any manner whatsoever.

If an arbiter saw you do this (deliberately touch two pieces simultaneously with one hand) then they would likely immediately warn you. If the opponent claimed that it was an annoyance you might receive more than a warning.
Repeat infringements would put you at risk of:

11.7 Persistent refusal by a player to comply with the Laws of Chess shall be penalised by loss of the game. The arbiter shall decide the
score of the opponent.

In extreme circumstances (I cannot think of any time this has been invoked) the arbiter could punish you under:

11.1 The players shall take no action that will bring the game of chess into disrepute.


A question regarding "The Horse Concoction"

This is just the very beginning of what must have been Goldsteen's demonstration, but if anyone wants to carry on from here...
Let's try and build the position after White's key move.
The bNh8 cannot be pinned, so there must be "blockading" knights on f7 and g6, that are pinned themselves.
Because squares f7 and h7 are occupied, the bNg6 cannot be pinned diagonally. It cannot be pinned vertically either, otherwise we cannot pin the bNf7. Hence it is pinned horizontally, leftwards.
The bK cannot be on f6 because there wouldn't be enough space to set up a pin on the f6-h8 diagonal. It cannot be too far from the bNf7 either, so you can conclude that the bK stands on e6.
The space available (or lack thereof) allows us to define the positions of four more pinned knights and four pinning pieces, leading to this position:
[FEN "2B1R1Bn/3nnn1P/1PRnk1nR/3nn3/2B4P/1P6/8/5Q2 w - - 0 1"]

Two remarks:

The wQf1 (or even a wP, although it seems unlikely) might have moved with the key move, I just put it on the diagram as a reminder that it had to be there before.

Each wB or wR might be replaced by a wQ.

There will be two additionnal bN's, and two pinning pieces, on the e-file and on the e6-h3 diagonal.
To go further, I suppose we might discuss cases depending on the locations of these two bN's. A very important point is that Black must be winning if White doesn't stalemate, so most probably wK willl be under check by the 10th knight (as in the solution with a bNh1) to avoid allowing scores of possible first white moves. Most probably too, the bK will also have a free square to escape to, thus unpinning half of its army.

Second step:
White already has three promoted pieces on the diagram. Since adding two more of them would be illegal (due to the remaining four wP's), it means that one of the last pinning pieces must be either the wQ or the wPh7.
There are only five possible stalemating key moves to consider:

Ph7xNg8:B or Ph7xNg8:Q (these ones are very unlikely because they cannot be check-parrying moves)
Qf1xNh3
Qf1xNe1
Qf1xNe2

As a consequence, the positions of the wP's on b3, b6, and h4 are certain.
Let's consider that White's key move is 1.Qf1-takes-the-knight-that-was-checking-white-King and try now to infer where the wK might stand.
Given that the wK cannot be on f4 or g5 (these squares are controlled by other bN's), the available square that is closest to the cluster of black pieces is d4, with d3 and f3 second-order possibilities. Because it is very hard to imagine Black, who is down scores of material, to be winning against a far-away wK (say, on c1), putting the wK on d4 could be the most logical next step.
As a consequence, the pinned bN on the e6-h3 diagonal cannot be on f5, and must stand on g4. To limit wK freedom, it is tempting to put the 9th knight on e5 (controlling d3), but it might also be on e3 or e4.
Which leads to this diagram before the key move:
[FEN "2B1R1Bn/3nnn1P/1PRnk1nR/3nn3/2BK2nP/1P5B/4n3/5Q2 w - - 0 1"]

But this leads to several new difficulties:

The key move 1.Qxe2 is not stalemating in spite of the 8 pins, since black can play 1...Kf6 or 1...Kf5. Of course, adding more (non-promoted) units, e.g. wNg3, wBg5, might still be possible.
(Notice that if we add chosen the setup wKd3/bNe4/bNe1 instead, we would also need to cover square e5; but then, the bNg4 could be on f5 blocking one flight square...)

We have to demonstrate a black win after the alternative capture 1.Bxe2, or make it impossible by adding a wNd3.

In both case, adding white units reduces the number of previous captures by Black, and is very likely to be impossible while keeping the legality of the position (less captures means less paths to promotions for both sides).
The alternative, in case adding a wB would still allow all the promotions, is:
[FEN "2B1R1Bn/3nnn1P/1PRnk1nR/3n1n2/2B1n2P/1P1K3B/8/B3nQ2 w - - 0 1"]

[Ba1 could be on b2,c3,d4,g7]
[If this is legal - edit: it is not]
Then we really have a stalemate after 1.Qf1xe1, but demonstrating a Black win after the alternative 1.Ke2 is a long shot, since only two black units can move! The best try would be to put wBa1 on c3 and play 1...Nxc3+ followed by 2...Ke5 or 2...Kf6, but that would allow yet another variation starting with 1.Bxe1! And still... (funnily enough, 1...Ng3+ 2.Kxe1 Nxf1 3.Kxf1 is another stalemate, and if Black cannot win the wQ at once he should not dream of a long-term win and has to checkmate quite forcefully)

The third step should be retrograde analysis to prove that we cannot add a white knight nor a dark-squared bishop.
Edit: this step is actually pretty easy: Black needs three captures to promote all his pawns: one by the b-pawn, one by the h-pawn, and one by the e-pawn or the c-pawn to allow the opposing white pawn to promote on a light square.
As a consequence, the third diagram above is illegal.
With a key move by the wQ, even without the stipulation that it should be the only move to prevent a defeat, I am thus unable to even reach a legal stalemate. [but I will not pretend I am 100% confident about all this reasonning; dear reader, please double check!]
The possible key moves that remain, because they allow more pieces to be present, are the non-check-parrying 1.h7xNg8:B and 1.h7xNg8:Q.
I am pretty convinced that they cannot be mandatory to prevent defeat (and thus, that Harry Goldsteen is right - not a surprise!), but step four will be to...

Step four
build a legal 9-knights stalemate starting with 1.h7xNg8:B
I believe this is achieved by the following position:
[FEN "2B1R1nn/3nnn1P/1PRnk1nR/3nn3/2BK2nP/1P5B/8/4RQ2 w - - 0 1"]

1.h7xNg8=B is stalemate
However, Black is clearly not winning after any other White move. Indeed, White has a direct mate in 1 with
1.Bxg4# or 1.Bxd5#
Convincing oneself that it is really mate is a little mind-boggling with all these pinned defenders who cannot defend.
I may spend a bit more time and sweat to prove properly that this last position is legal, but I will stop thereafter. After reaching that point, I am totally convinced that Goldsteen's assertion that "there is no solution to the Horse Concoction with a bNh8" is absolutely correct.
Addednum-Here is game that proves it is legal. Due to the page freezing, it can be played out on apronus.com.
Move List: 1. a4 a5 2. h4 h5 3. g4 e5 4. g5 Rh6 5. gxh6 d5 6. f4 Bd6 7. d4 e4 8. Na3 g5 9. Nc4 e3 10. Nd2 exd2+ 11. Kf2 Be5 12. dxe5 g4 13. e4 Qg5 14. fxg5 f5 15. b3 Ra6 16. Ba3 b5 17. h7 Rb6 18. g6 b4 19. g7 Rb5 20. axb5 bxa3 21. c4 c5 22. Nh3 Bd7 23. b6 Bb5 24. cxb5 g3+ 25. Ke2 g2 26. Nf2 f4 27. Ng4 hxg4 28. b7 f3+ 29. Ke3 d4+ 30. Kf4 g3 31. e6 f2 32. e5 g1=N 33. Bh3 g2 34. e7 Kf7 35. e6+ Kf6 36. e8=B a2 37. e7 a4 38. Bf7 a3 39. e8=B c4 40. Bed7 c3 41. Bc8 Nd7 42. b8=R d3 43. Bb7 c2 44. Re8 Ne7 45. Bc4 f1=N 46. g8=R c1=N 47. b6 Nf3 48. Bb5 Nfe5 49. Qe1 Nf7 50. Rh2 g1=N 51. Rb1 d1=N 52. Rg5 Nf2 53. Rh5 Ng4 54. Rc2 d2 55. Ke4 d1=N 56. Rcc5 Nc3+ 57. Kd4 Ncd5 58. Bc4 Nfe3 59. Rb2 N3f5+ 60. Ke4 N5h6 61. Kd4 Nhg8 62. Ke4 a1=N 63. Rd2 Nf3 64. Qe2 N3e5 65. Qe1 N5g6 66. Qe2 Ngh8 67. Qe1 Nc2 68. Qe2 Ne1 69. Rd1 a2 70. Qg2 a1=N 71. Qg1 Nac2 72. Qf1+ Ke6 73. Bc8 Nce3 74. Kd4 N3f5+ 75. Ke4 N5d6+ 76. Kd4 Ncd3 77. Rc6 N3e5 78. Rc1 N1d3 79. Re1 N3f4 80. Rh6+ Nfg6


Knowing when to play Nc6 vs Nbd7 in the Najdorf Sicilian as black?

Well it all "depends" on the position, but in the given example,   Nc6 is a better option as it has a possible outpost on d4 or b4 and with the rook on c8 it will also be doubly defended. It can even be re-routed to f6  if required which would be almost impossible from d7. Nbd7 does block the defense of the d6 pawn. BTW , I  saw a study somewhere that countering the najdorf the d6 pawn is to be targeted therefore it is suggested not to make it a liability in the first place ( of course this might be valid in high level games only). Here is a study where majority games I saw played Nbd7 but I am not a GM and can't quite follow the reasoning. If your opponent castles long then definitely put the knight on d7.


Here are some ideas about whether or not a source can be trusted.
-Not all titled players are good in teaching.
-Chess.com is great because its members are excellent chess players and will not allow a poor article or video to be published.
-chess.about.com is good because it hires professional people, but not as good as chess.com
-thechesswebsite.com is great because kevin (the man behind the site) has many subscribers on youtube, kingcrucher is another great youtube channel because it offers in depth analysis, but they focus too much on blitz.
and then you have Roman's lab, Roman is the greatest chess teacher of all time.
What else do you have? When looking at books, you can check the Amazon rating and reviews.


Is it bad form to go for a lengthy but losing endgame that you suspect will be winning on time?

All is fair in love, war, and blitz (at least with regards to winning on time, and short of outright cheating).

In blitz, time is a major factor in the game, and it is fine to try and win on time in any situation.

If you used too much time, and your opponent thinks he can flag you, there is nothing wrong with that. It is part of the game.

I have seen Grandmasters check with a queen right next to the opposing king that can be taken for free to win on time, just because it requires that split second to realize what happened.

P.S. If someone does not like being flagged, they can always play with an increment.


Sacrificing a piece on f7 (via Nf3-g5-f7 or e4, Bc4, Bxf7) creates a hole on f7 which can later be filled by a parachuting piece. This can be quite effective particularly if you have paratroopers ready from your partner's game.


This question can hardly have an objective answer, as the time controls and the strength of the players both matter a lot while valuing material and time management. A partial answer would be given assuming a time control of 1 minute. For this time control, regardless of the strength of the players, we can safely say that on lost positions the knight is the most valuable piece (after the queen). This is stated many times by IM Daniel Rensch on his Bullet Brawl Series.

When the player possessing the knight has more time, this difference is accentuated as he may look for tricks and swindles to try to make his opponent blunder or even lose on time. The forking ability of the knight is what makes it such a good piece in bullet, as some times the fork occurs and the knight cannot even be captured after he wins one of the forked pieces. This advantage is almost completely nullified when there is some kind of increment, allowing the players to take their time and think a bit more about the position.


Play against a computer, but only with a few pieces and without the kings

No engine that I’ve ever come across has this functionality. In fact it would actually be surprisingly difficult to get a chess engine to do this;
The most fundamental rule of chess is that you have to checkmate your opponent’s king. A position without kings on the board wouldn’t make sense to something like Stockfish, because the game ends before the king can be captured. If you don’t have kings on the board, you essentially have to rewrite the rules of the game for the engine. This would also have the knock-on effect that, because king safety it widely considered the most important consideration in chess, you would then have to re-programme how the engine analyses the board, as king safety would no longer be a thing. By this point, once you have an engine which has different game rules and a different way of analysing the game, it doesn’t really make sense to say that it’s the same engine, but rather two different engines playing two different games. Long story short; you couldn't give a position without kings to a normal chess engine and expect to get a meaningful analysis back.
If you wanted to get around this, you could set up a position where both kings are in the opposite corner, so that they’re far enough away from the action that they couldn’t get there in time to help (assuming it’s something like 3 pawns vs a knight). Alternatively, you could set up the position on a board and play against yourself, trying to find the best move for both sides.
tl;dr – You would have to build an engine with this specific scenario in mind for it to work.


Program for determining the type of opening / endgame

Scid using stockfish will do this. And on iOS I use the Stockfish app to do this.