<p>The current testnet is on its third iteration, somewhat unimaginatively titled testnet3.</p>
<p>It was put that way by <a href="https://github.com/bitcoin/bitcoin/commit/feeb761ba07af74a7cd78b8c8f7c2a961fd9ea1c" rel="nofollow noreferrer">this commit</a>:</p>
<blockquote>
<p>Testnet, Mark III</p>
</blockquote>
<blockquote>
<p>gavinandresen authored 2012-04-12</p>
</blockquote>
<p>Before that, we had <a href="https://github.com/bitcoin/bitcoin/commit/98ba262a48b66cae8478525e809898512e997948" rel="nofollow noreferrer">testnet2</a>: (though we didn't call it that back then)</p>
<blockquote>
<p>Reset testnet with a new genesis block</p>
</blockquote>
<blockquote>
<p>davout authored 2011-02-03</p>
</blockquote>
<p>Before that, <a href="https://github.com/bitcoin/bitcoin/commit/5cbf75324d1509a1262b65c5073314a4da3f6d77" rel="nofollow noreferrer">testnet</a>:</p>
<blockquote>
<p>Gavin's TEST network as -testnet switch, misc fixes
git-svn-id: <a href="https://bitcoin.svn.sourceforge.net/svnroot/bitcoin/trunk@168" rel="nofollow noreferrer">https://bitcoin.svn.sourceforge.net/svnroot/bitcoin/trunk@168</a> 1a98c847-1fd6-4fd8-948a-caf3550aa51b</p>
</blockquote>
<blockquote>
<p>s_nakamoto authored 2010-10-19</p>
</blockquote>
<p>Man, sourceforge. Brings ya back, doesn't it?</p>
<p>Essentially, the devs want testnet coins to be worthless for two reasons:</p>
<ol>
<li>to make them easy to mine</li>
<li>because it's nice to have a place to demonstrate attacks against bitcoin without actually disrupting the network. You can show that an attack is valid without costing people real money.</li>
</ol>

CC BY-SA 3.0
2015-04-07T13:36:18.163Z
Also note that the testnet3 commit mentioned by @Nick does not specify a new timestamp for the genesis block. Thus, most testnet blockchain explorers will display the testnet2 genesis date ('2011-02-02') for block '#0' (instead of the actual testnet3 genesis date, which is something '2012-04'ish). This can be a major source of confusion. Also, it appears that between blocks 513 and 514 a sudden temporal shift occurs as the block time jumps from '2011-02-03' to '2012-05-24' unexpectedly.
Priidu Neemre
CC BY-SA 4.0
2013-04-19T07:43:02.727Z
2024-01-21T20:36:47.837Z
2024-01-21T20:36:47.837Z
Nick ODell
<p>The Bitcoin TestNet is a network identical to Bitcoin in every respect except that the bitcoins on it are worthless because no one accepts them in payment or values them for anything other than testing purposes.  In essence, TestNet btc are valuable <em>because</em> they are worthless, allowing for useful experimentation when developing.</p>

<p>I read somewhere that <strong>one way the TestNet can be prevented from acquiring significant value and mining power is by being reset from time to time</strong> so that TestNet btc remain easy to mine and acquire for testing purposes.  This made me curious--<strong>has this ever happened before?</strong></p>

<history><testnet>
Has the TestNet ever been reset?
eMansipater
# Has the TestNet ever been reset?

(Asked by: username_0 on 2013-04-19)

The Bitcoin TestNet is a network identical to Bitcoin in every respect except that the bitcoins on it are worthless because no one accepts them in payment or values them for anything other than testing purposes. In essence, TestNet btc are valuable *because* they are worthless, allowing for useful experimentation when developing.

I read somewhere that **one way the TestNet can be prevented from acquiring significant value and mining power is by being reset from time to time** so that TestNet btc remain easy to mine and acquire for testing purposes. This made me curious--**has this ever happened before?**

**Tags:** history, testnet


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## 1 answers

### Answer by username_1 on 2013-04-19. Score: 13 | Accepted answer

The current testnet is on its third iteration, somewhat unimaginatively titled testnet3.

It was put that way by [this commit](https://github.com/bitcoin/bitcoin/commit/feeb761ba07af74a7cd78b8c8f7c2a961fd9ea1c):

> Testnet, Mark III

> gavinandresen authored 2012-04-12

Before that, we had [testnet2](https://github.com/bitcoin/bitcoin/commit/98ba262a48b66cae8478525e809898512e997948): (though we didn't call it that back then)

> Reset testnet with a new genesis block

> davout authored 2011-02-03

Before that, [testnet](https://github.com/bitcoin/bitcoin/commit/5cbf75324d1509a1262b65c5073314a4da3f6d77):

> Gavin's TEST network as -testnet switch, misc fixes
> git-svn-id: <https://bitcoin.svn.sourceforge.net/svnroot/bitcoin/trunk@168> 1a98c847-1fd6-4fd8-948a-caf3550aa51b

> s\_nakamoto authored 2010-10-19

Man, sourceforge. Brings ya back, doesn't it?

Essentially, the devs want testnet coins to be worthless for two reasons:

1. to make them easy to mine
2. because it's nice to have a place to demonstrate attacks against bitcoin without actually disrupting the network. You can show that an attack is valid without costing people real money.

> **Comments:**
> **username_2**: Also note that the testnet3 commit mentioned by @username_1 does not specify a new timestamp for the genesis block. Thus, most testnet blockchain explorers will display the testnet2 genesis date ('2011-02-02') for block '#0' (instead of the actual testnet3 genesis date, which is something '2012-04'ish). This can be a major source of confusion. Also, it appears that between blocks 513 and 514 a sudden temporal shift occurs as the block time jumps from '2011-02-03' to '2012-05-24' unexpectedly.  

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