Only Chess
04 Apr 05
05 Apr 05
Originally posted by RedmikeInteresting puzzle.
Qa7 is indeed the correct solution.
Black then has a variety of legal moves, but they all allow mate in 1.
Eg:
...any knight move allows 2.Nb6;
...Be7 allows r6xd7;
...f5 allows Nd5;
...c6 allows bxc6
I checked your solution with a couple engines and found a truly curious situation:
Hiarcs and Fritz both found one of several mate in three solutions, and then quit looking. Crafty did the same, until I installed the newest version that I downloaded yesterday. It found the solution in a few seconds.
Anaconda 1.6, on the other hand, found the solution instantly on a P3 machine, as did Anaconda 2.0 on a P4.
I haven't yet run Fritz on the P4, and I have about 64 more engines that can look at the problem. But, I cannot recall another mate in two that any of the leading engines had any trouble with. Usually the solution is instantaneous. Weaker engines, such as T-rex, sometimes require 5-10 seconds, but solve most mate in twos.
I'm perplexed.😕
05 Apr 05
Originally posted by WulebgrEven engines cannot match divine inspiration, it seems.🙂
Interesting puzzle.
I checked your solution with a couple engines and found a truly curious situation:
Hiarcs and Fritz both found one of several mate in three solutions, and then quit looking. Crafty did the same, until I installed the newest version that I downloaded yesterday. It found the solution in a few seconds.
Anaconda 1.6, on the other han ...[text shortened]... such as T-rex, sometimes require 5-10 seconds, but solve most mate in twos.
I'm perplexed.😕
05 Apr 05
Originally posted by WulebgrHave you tried running Fritz in Mate Search mode?
Interesting puzzle.
I checked your solution with a couple engines and found a truly curious situation:
Hiarcs and Fritz both found one of several mate in three solutions, and then quit looking. Crafty did the same, until I installed the newest version that I downloaded yesterday. It found the solution in a few seconds.
Anaconda 1.6, on the other han ...[text shortened]... such as T-rex, sometimes require 5-10 seconds, but solve most mate in twos.
I'm perplexed.😕
If I do that it finds it instantly.
The key is that Mate Search looks at every move rather than pruning. That way it can be sure it hasn't missed a mate at a given ply at the expense of speed.
06 Apr 05
Originally posted by XanthosNZnow, why didn't I think of that 😳
Have you tried running Fritz in Mate Search mode?
If I do that it finds it instantly.
The key is that Mate Search looks at every move rather than pruning. That way it can be sure it hasn't missed a mate at a given ply at the expense of speed.