“How To Solve Chess Problems” by Kenneth S. Howard 2nd Revised Edition, Dover Publications, New York 1961.
The problem is #112 Otto Wurzburg - First Prize Third Cheney Miniature Tourney 1937. White mates in four moves.
8/8/8/p7/R4B2/8/5k2/1B5K w - - 0 1
After trying to figure out this tough problem I decided to use Shredder Classic 3 that I just downloaded to see what it came up with. I was stunned when it said it was a mate in 5. I thought Shredder was one of the top pieces of software available.
I checked the answer in the back of the book and the book seemed to be correct. I also entered the position in Chessmaster 10th Edition and it solved the mate in 4 instantly. Why didn’t Shredder calculate the mate in 4?
I also went on the shredder website and typed this problem in the Endgame Database and it instantly figured it out as a Win in 4. Does anyone know why Shredder Classic 3 did not calculate this problem correctly, or is there something that I’m missing? Also, does anyone have Fritz 11 or maybe Deep Shredder that they can check this problem with? I wonder what those programs come up with.
Computer engines are not designed to solve tricky mates and it is possible to create examples that will confound even the top programs. Many of them stop calculating once they find one checkmate. Fritz 11, Rybka 2.3 and Crafty 20 all say mate in 5; Junior 9 even tells me mate in 16!? Only Mate 2.16, a Chessbase program designed to calculate the fastest mate, finds the key.
Thanks Michael, that makes sense. I was just shocked that “The Chessmaster 10” found it instantly, and Shredder found it as a mate in 5. I thought maybe my engine settings were wrong or needed to be adjusted.
If you take Fritz out of its normal game playing mode (such as by Shift+Ctrl+M), then Fritz finds c78/B instantly when you click the green ‘Go’ button.
I suspect Fritz would also find the promotion-to-bishop move if its game playing mode had been set to FixedDepth, instead of its default of Time (but I have not tested it).
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The Chessmaster instantly calculated that one as well. Shredder calculated a mate in 5 with a Queen promotion. I was interested in buying Shredder, but it seems the Chessmaster is a pretty good program for everything that I need. Basically I do a lot of chess puzzles, play games (against the computer) and I try to go over games as well. I think my playing strength is above 1581, which was my rating from 1990. I haven’t played in a tournament since then. I like to use Chessmaster to analyze positions to see what it would do, or see how it would play out an endgame, etc.