Great site! But ...

[winbyforce]

This is a great site! And its free!!

I have just 1 complaint, and its about the problems. Many problems have more than 1 winning line, if you dont get the "best" line, you dont get points for almost solving the problem... kinda unfair.

Anyone else noticed this?

[richard]

For non-mate moves, the problem generator sets an ambiguity threshold so that the "best" move has to be at least a couple of pawns better than the second best move. For non-mate tactics there are also some heuristics that attempt to remove positions where there are two big winnings moves but one happens to be 2 pawns more 'winning' than the other.  These heuristics are not perfect but appear to remove most of the problematic positions.

For moves ending in mate the "best" move is always the shortest mate.  As far as  I know there are no problems in the set where there are two equal shortest mates possible. Unfortunately this means that if you find a mate in 3 but there is a mate in 2 then you will get no credit.  Similarly if you find a queen sack but miss a mate in 6 then you will also get no credit as the mate in 6 will override the queen sack as the best move even though both will win eventually. 

There is more room for improvement , especially in the treatment of mate moves and I'm in the early stages of experimenting with some improvements in this area.  I will be uploading a large number of problems produced with the old generator before the end of the coming weekend, after that I can concentrate on further improving the generator.

Regards,
Richard.

[saponaro]

Im fine with it the way it is, makes me really think when i can smell a mate! But i wouldnt be opposed to half-credit for a mate in 3 instead of a mate in 2.