TalkChess.com

[H.G.Muller]

I think that you are overlooking that WCCC rules have to be more strict than copyright rule.

Copying ideas is OK according to copyright law
Copying ideas might not be OK for WCCC

At least, if the gray area of eval parameters and engine tuning are considered ideas. (And, according to copyright law, it would be allowed to copy them, so heaping them with the ideas makes sense.)

We don't want to have 5 independently coded but identically playing engines participating in the WCCC. (Which have the same move ordering, the same extensions, the same reductions, the same eval terms, the same eval parameters... But totally different code and data structures.) The WCCC is not intended to be an instrument for measuring who could most efficiently implement the same algorithm, or which of its implementers is simply most lucky. There could be contests for that too, and they might even be interesting and beneficial to the computer Chess community. But it is ICGA's choice for the WCCC to not be such an instrument, and it is their privilege to decide that, because it is their tournament. If others want to organize an IppoCloners or FruitMash Contest, they are free to do so. And they could disqualify anyone for making an entry that did not look enough like Ippo, because they cheated by using an _original_ evaluation term that improved Elo...

So we somehow have to better define the gray area (not gray in copyright law. but according to competition rules) of implementing 'ideas'. Some ideas are public-domain knowledge, or even mathematically proven optima (minimax, alpha-beta), and it would be silly to force anyone to stray from a generally known optimum just to count as original. This is one extreme of the spectrum. The other extreme is ripping the complete evaluation from a specific engine, and (after recoding) use it in your own. I would say this should not be allowed in competition rules even if the engine in question was open source, like Fruit. Completely recoded Fruits would still not be welcomed.