Jouni wrote:I have sent some correction to Franz and have feeling, that 2-5% of Chest database positions are incorrect e.g. there is a shorter mate.
2-5% ? That would be 100-300 mates???

Well, I'm sure that's much too high!
Of course there are some incorrect mates, but it's not ChestUCI's fault but the fault of the problem composers!
If I find a mate problem and the composer states it is a mate in N, then I try to find a mate in N, and if ChestUCI finds such a solution, then I usually see no reason trying to find a mate in N-1, N-2, etc. ...
That would take just too much time on my quite slow computer.
Just today I've updated the ChestUCI database on my website, where I've fixed all incorrect mates which were reported in the last time.
But I don't trust mate announcements of normal chess engines very much, e.g. Rybka reported three #9 in Jouni's test suite in this thread, which were in fact #11 (checked even in brute force mode).
So if someone finds any shorter mate than reported in the ChestUCI database with a normal chess engine, then he should try to get a solution with ChestUCI and post this solution with the special parameters and solution time found, otherwise I won't be able to prove this here on my system.
Regards,
Franz