Author: Bruce Moreland
Date: 21:22:31 06/25/98
Go up one level in this thread
On June 25, 1998 at 23:19:32, Robert Hyatt wrote: >On June 25, 1998 at 21:45:15, Robert Hyatt wrote: > >>On June 25, 1998 at 19:25:39, Bruce Moreland wrote: >> >>> >>>On June 25, 1998 at 16:18:29, Robert Hyatt wrote: >>> >>>>Bruce is doing some extension stuff that might well pick this up quickly, >>>>as Cray Blitz gets this right at 5 plies and 0 seconds, but the PV is quite >>>>long and has the horizon moves by white correct, and it realizes that black >>>>*has* to stop to capture each pawn that is offered, but it discovers that >>>>those moves are "singular" and it extends them quite deeply. I'm not yet >>>>doing singular extensions in crafty, so I don't catch this so quickly, but >>>>I'm starting to play with them again to see if I like the result. >>> >>>Nope, nothing weird here, just null move with maybe some conservative and >>>minimal pawn push extensions and some razoring. >>> >>>I find it in 9 plies, but it's +2 until 14 plies, at which point it goes up to >>>+5. >>> >>>If this contradicts anything in my original post on this, it's because I've >>>changed versions and machines (trivial version changes). >>> >>>bruce >> >> >>can you post your 9 ply PV? the problem I have at 9 plies is that white has >>a few threats of his own. Starting with h4 and black has to retake... then >>another pawn push that black has to take time out for. Without those, this is >>an easy position, but each white pawn push requires a capture by black or white >>gets a queen first. This is what hurts my search... > > > >this is an interesting position. I just ran some analysis. First, here >is my 9 ply search: > 9-> 0.25 -0.03 1. ... Ra3 2. Rxa3 bxa3 3. g4 Kd5 4. > g5 Kd6 5. h5 gxh5 6. Kh4 > > >this is cute. Ra3 Rxa3 bxa3 are forced. g4 is cute as now black has >to do something besides go after the a-pawn, else g5 and h4 queens first. >Crafty understands the threatened promotion, so keeps the king in the square >of the potentially passed h-pawn... > >within 9 plies, I obviously can't solve this. > >here's additional searches, showing what I see. I don't understand this >until ply=12: > > 10 0.53 -- 1. ... Ra3 > 10 0.76 -0.51 1. ... Ra3 2. Rxa3 bxa3 3. g4 Kd5 4. > g5 e5 5. h5 gxh5 6. g6 Ke6 7. g7 > 10-> 0.77 -0.51 1. ... Ra3 2. Rxa3 bxa3 3. g4 Kd5 4. > g5 e5 5. h5 gxh5 6. g6 Ke6 7. g7 > 11 1.12 -0.71 1. ... Ra3 2. Rxa3 bxa3 3. g4 Kd5 4. > g5 e5 5. h5 gxh5 6. g6 Ke6 7. g7 Kf7 > 11-> 1.13 -0.71 1. ... Ra3 2. Rxa3 bxa3 3. g4 Kd5 4. > g5 e5 5. h5 gxh5 6. g6 Ke6 7. g7 Kf7 > 12 2.44 ++ 1. ... Ra3!! > 12 4.17 2.46 1. ... Ra3 2. Rxa3 bxa3 3. h5 gxh5 > 4. Kh4 Kc3 5. Kxh5 Kb2 6. g4 fxg4 7. > Kh4 Kxa2 8. Kxg4 > 12-> 4.19 2.46 1. ... Ra3 2. Rxa3 bxa3 3. h5 gxh5 > 4. Kh4 Kc3 5. Kxh5 Kb2 6. g4 fxg4 7. > Kh4 Kxa2 8. Kxg4 > >big question is, now, how is Ferret seeing this at depth=9, because it >looks quite tricky for both sides to me. What is Crafty overlooking here? PV 00:00:00.592 9 35 [wrong] Ra3 PV 00:00:00.602 9 107 [wrong] Ra3 PV 00:00:00.633 9 248 [wrong] Ra3 Rxa3 bxa3 g4 Kc3 Kg3 Kb2 h5 gxh5 gxf5 PV 00:00:00.756 10 198 [wrong] Ra3 Rxa3 bxa3 g4 Kc3 h5 fxg4+ Kxg4 gxh5+ Kxh5 Kb2 Kg5 Kxa2 Kf6 Kb1 I think it failed low then failed high in ply 10, but I don't know for sure, this is odd. PV 00:00:00.825 11 198 [wrong] Ra3 Rxa3 bxa3 g4 Kc3 h5 fxg4+ Kxg4 gxh5+ Kxh5 Kb2 Kg5 Kxa2 Kf6 Kb1 Kxe6 PV 00:00:01.673 12 188 [wrong] Ra3 Rxa3 bxa3 g4 fxg4+ Kxg4 Kc3 Kg5 Kb2 Kxg6 Kxa2 f5 exf5 Kxf5 Kb2 PV 00:00:02.336 13 190 [wrong] Ra3 Rxa3 bxa3 g4 fxg4+ Kxg4 Kc3 Kg5 Kb2 Kxg6 Kxa2 f5 exf5 Kg5 Kb1 Kxf5 PV 00:00:03.173 14 240 [wrong] Ra3 Rxa3 bxa3 g4 fxg4+ Kxg4 Kc3 Kg5 Kb2 Kxg6 Kxa2 f5 exf5 Kg5 Kb1 Kxf5 PV 00:00:04.468 14 515 [wrong] Ra3 Rxa3 bxa3 h5 gxh5 Kh4 Kc3 Kxh5 Kb2 g4 fxg4 Kg5 Kxa2 Kf6 g3 PV 00:00:09.230 15 446 [wrong] Ra3 Rxa3 bxa3 h5 gxh5 Kh4 Kc3 Kxh5 Kb2 g4 fxg4 Kh4 Kb1 f5 exf5
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