Author: Dan Simmons
Date: 14:43:23 05/07/03
In the diagram, it is White to move and win with the concept of interference in this composition. [D] 8/6b1/5k2/8/P3K2P/8/8/8 w - - 0 1 My solution involved 1.g5+ Kxg5 2.a5 Bf8 3.Kd5 with a white win. It didn’t occur to me until after I saw that I had missed the correct solution that maybe Black doesn’t have to recapture on his first move but can instead try 1…Ke6. Well, let’s see what the grandmaster computer has to say. I set up the position in F8 (ver 23) on a PIII, 1.2Ghz, 64MB hash. I played 1.g5. Fritz immediately selects 1…Kxg5 and never changes for at least 15 minutes of thinking, declaring the position dead even after 2. a5 Bf8 3. a6 Bc5. Fritz gives equal weight (0.00) to 1…Ke6 but selects Kxg5. Say what? After 15 minutes, I couldn’t find Fritz8 even considering 3.Kd5 in its search on move 1. So I allowed Fritz to play 1…Kxg5 and I played 2.a5. Despite the time control being 20 minutes/move, Fritz plays 2…Bf8 after seven seconds and declares the position a draw, only considering 3.a6 in its search window. I then play 3.Kd5 and Fritz’ evaluation shows a win for white in 2 seconds. I then moved back to the position after 2.a5 and set time for infinite. Fritz only thinks for seven seconds then the engine clock (as opposed to the game clock) stops and no further searching is apparently done. At this point, Fritz is still evaluating as a draw with 2…Bf8 3.a6 Bc5. Thinking that was a freaky bug, I then went back to the original position and allowed Fritz to analyze. It fails to find the correct solution 1.a5 Bf8 2.Kd5 Bh6 3. g5+ Bxg5 4.Ke4 Bh4 5.Kf3 with a white win. Fritz selects 1.a5 but then selects the drawing 2.a6? after black’s Bf8. Per the search window, F8 never considers Kd5. I then advance the solution another move but Fritz as white again fails to even consider the simple king move that wins: 4.Ke4. Interestingly, only after Fritz8 is forced to play 2.Kd5 and 4.Ke4 does it see the win. After 4.Ke4, it finds the win immediately in 00:00 Is this a Fritz problem? I dunno. In the same GUI, Fritz 5.32 finds the win immediately from the original position and has no problem rejecting 1…Kxg5 after my chosen 1.g5+?. Unfortunately, I am on my laptop which has only 8.0.0.23 rather than my desktop which also has 8.0.0.8 to see if there is a difference in this bug between the versions. Comments?
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