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I'm looking for a chess opening database that is reasonably complete and computer-readable. It should be available either under a liberal free license (like, say, CC-BY, no GPL), or under reasonable commercial license.

Are there any?

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no GPL is difficult, could you expand on the "reasonable commercial license"? – Helio Dec 7 '12 at 0:46
Well, some kind of reasonable one-time payment would be ideal. (With commercial use rights, of course.) – Alexander Gladysh Dec 8 '12 at 7:58


The reason for a no, lies in your question. If you want "liberal free license" you are asking for free software and “free software” is a matter of liberty, not price, since you specifically said "(no GPL)" then your request is contradictory.

However, if you do want “free” (as in “free speech,” not as in “free beer”) opening database, there are some options.

You can build small (1 MB), medium (25 MB), or large (58 MB) opening books for Crafty, that will give you enough material for a couple of years, maybe even more.

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Lets just say that GPL is not my kind of free. Say, CC-BY would be much better. Note that I'm looking for data, not software, and not to teach myself, but for commercial use (or GPL would be just fine). I'm okay to pay for that, BTW. – Alexander Gladysh Dec 25 '12 at 4:10

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