Type of Grid
Crossword grids such as those appearing in most North American newspapers and magazines feature solid areas of white squares. Every letter is checked, and usually each answer is required to contain at least three letters. In such puzzles black squares are traditionally limited to about one-sixth of the design. Crossword grids elsewhere, such as in Britain and Australia, have a lattice-like structure, with a higher percentage of black squares, leaving up to half the letters in an answer unchecked. For example, if the top row has an answer running all the way across, there will be no across answers in the second row.
Another tradition in puzzle design (in North America and Britain particularly) is that the grid should have 180-degree rotational symmetry, so that its pattern appears the same if the paper is turned upside down. Most puzzle designs also require that all white cells be orthogonally contiguous (that is, connected in one mass through shared sides, to form a single polyomino).
The design of Japanese crossword grids often follows two additional rules: that black cells may not share a side and that the corner squares must be white.
Substantial variants from the usual forms exist. Two of the common ones are barred crosswords, which use bold lines between squares (instead of black squares) to separate answers, and circular designs, with answers entered either radially or in concentric circles. Free form crosswords have simple designs and are not symmetric. Grids forming shapes other than squares are also occasionally used.
Puzzles are often one of several standard sizes. For example, many weekday puzzles (such as the New York Times crossword) are 15×15 squares, while weekend puzzles may be 21×21, 23×23 or 25×25.
Typically, clues appear outside the grid, divided into an Across list and a Down list; the first cell of each entry contains a number referenced by the clue lists. For example, the answer to a clue labeled "17-Down" is entered with the first letter in the cell numbered "17", proceeding down from there. Numbers are almost never repeated; numbered cells are labeled consecutively, usually from left to right across each row, starting with the top row and proceeding downward. Some Japanese crosswords are numbered from top to bottom down each column, starting with the leftmost column and proceeding right.
Some crosswords do not number the clues, but have their clues in small print inside grid cells which act as blanks, each clue with a little arrow indicating in which direction from its initial cell the answer is to be written. This kind of crossword originated in Scandinavia and has many different names: "Arrowwords", "Pointers" or "Tipwords" in English, Autodefinidos in Spanish, "Mots Fléchés" in French, etc, and are very popular, often being printed larger than conventional crosswords (to allow adequate space for printing the clues) and are much-used in competitions.
Answers are printed in upper case letters. This ensures a proper name can have its initial capital letter checked with a non-capitalizable letter in the intersecting clue. Diacritical markings in foreign loanwords are ignored for similar reasons. In languages other than English, the status of diacritics varies according to the orthography of the particular language, thus:
- in French, in Spanish and in Italian, accent marks and most other diacritical markings are ignored: for instance, in French, the final E of answer ÊTRE can double as the final É of CONGÉ when written ETRE and CONGE;
- in German language crosswords, the umlauts ä, ö, and ü are dissolved into ae, oe, and ue, and ß is dissolved into ss.
- in Dutch crosswords, the ij digraph is considered one letter, filling one square, and the IJ and the Y (see Dutch alphabet) are considered distinct. Rules may vary in other word games.
- in Spanish crosswords, although ch and ll were once considered one letter each, they fill two squares.
- in Czech and Slovak, diacritics are respected and ch being considered one letter occupies one square.
- in Romanian, diacritics are ignored.