Author: Dann Corbit
Date: 13:00:17 06/06/00
Go up one level in this thread
On June 06, 2000 at 15:10:07, pete wrote: >On June 05, 2000 at 19:18:56, Pete R. wrote: > >>Here is the diagram Mr. Uri posted last week: >> >>[D]r2qr3/pb3pk1/np3b1N/2pp3Q/3P4/1PR1P1P1/P4PBP/5RK1 w - - 0 1 >> >>I let Fritz 5.32 run the weekend on it, and after a great deal of >>thought it decided the best move is...1. e4!!. >> >>Analysis by Fritz 5.32: >> >>-+ (-2.94) 1.dxc5 Bxc3 2.Nxf7 00:00:00 >>= (-0.25) 1.Nxf7 00:00:00 >>² (0.31) 1.Nxf7 00:00:00 >>= (0.25) 1.Nxf7 Qe7 00:00:00 >>³ (-0.47) 1.Nxf7 Qe7 2.Ne5 00:00:00 >>³ (-0.44) 1.Rfc1 00:00:00 >>³ (-0.41) 1.Rfc1 Qd7 2.Nf5+ Kg8 00:00:00 >>³ (-0.37) 1.Rd3 00:00:00 >>³ (-0.34) 1.Rd3 Qd7 2.dxc5 Nxc5 3.Nf5+ Kg8 00:00:00 >>³ (-0.31) 1.Qxf7+ 00:00:00 >>² (0.50) 1.Qxf7+ Kxh6 2.Qxb7 Nb4 00:00:00 >>= (0.06) 1.Qxf7+ Kxh6 2.Qxb7 Nb4 3.a3 00:00:00 >>= (0.09) 1.Nxf7 00:00:00 >>² (0.44) 1.Nxf7 Qd7 2.Ne5 Bxe5 00:00:00 >>² (0.53) 1.Nxf7 Qe7 2.Nh6 Rh8 3.Nf5+ Kf8 00:00:00 >>² (0.56) 1.Nxf7 Qd7 2.Nh6 Kf8 3.Nf5 Rac8 00:00:00 >>² (0.47) 1.Nxf7 Qe7 2.Nh6 Bc8 3.Qxd5 Nc7 4.Nf5+ Bxf5 5.Qxf5 cxd4 00:00:00 >>² (0.69) 1.Nxf7 Qc7 2.Nh6 Rf8 3.Nf5+ Kg8 4.f4 Rae8 5.Nh6+ Kg7 00:00:03 >>± (0.75) 1.Nxf7 Qc7 2.Nh6 Rh8 3.Nf5+ Kf8 4.Qg6 Bg7 5.Rd1 Rd8 00:00:08 >>² (0.69) 1.Nxf7 Qc7 2.Nh6 Rad8 3.Nf5+ Kf8 4.a3 Qf7 5.Qxf7+ Kxf7 00:00:24 >>± (0.81) 1.Nxf7 Qc7 2.Nh6 Rh8 3.Nf5+ Kf8 4.Qg6 Bg7 5.Bxd5 Bxd5 00:01:27 >>± (0.81) 1.Nxf7 Qc7 2.Nh6 Rf8 3.g4 Kh8 4.Nf7+ Kg8 5.Qg6+ Bg7 00:03:49 >>± (0.84) 1.g4 00:28:08 >>± (1.06) 1.g4 Rh8 2.Qxf7+ Kxh6 3.f4 Rg8 4.g5+ Bxg5 5.Qxb7 Nc7 01:22:25 >>± (1.00) 1.g4 Rh8 2.Qxf7+ Kxh6 3.f4 Rg8 4.Qxb7 Nc7 5.h3 Bg7 01:41:17 >>² (0.50) 1.g4 Rh8 2.Qxf7+ Kxh6 3.f4 Rg8 4.Qxb7 Nb4 5.g5+ Bxg5 04:56:05 >>² (0.53) 1.Nxf7 05:04:04 >>² (0.69) 1.Nxf7 Qd7 2.Ne5 Bxe5 3.dxe5 Qe6 4.f4 Rh8 5.Qg5+ Kf7 09:27:46 >>± (0.72) 1.e4 16:27:07 >>± (0.78) 1.e4 dxe4 2.g4 Rh8 22:38:47 >>± (0.84) 1.e4 dxe4 2.g4 Rh8 3.Qxf7+ Kxh6 4.Qxb7 Nc7 5.Rh3+ Kg7 37:03:44 >> >>Final depth reached is 16 ply. As you can see it took 16.5 hours on a PII >>400 to decide on 1.e4!!. According to my analysis (although not completely >>exhaustive) I do think this is the best move and white likely wins in all >>lines: >> >>1. e4!! dxe4 2. g4 Rh8 >> >>other tries: >> >> A) 2...Bc8 3. Qxf7+ Kxh6 4. Rh3+ Bh4 5. Qh5+ Kg7 6. Rxh4 Qf6 >> 7. Qxe8 Qxh4 8. Re1 +-. >> >> B) 2...Bh4 3. Nf5+ Kg8 4. g5 Qd7 5. g6 fxg6 6. Qxg6+ Kf8 7. Rg3 +-. >> >> C) 2...Bg5 3. Nf5+ Kf6 4. f4 exf3 5. h4 Bd2 6. Bxf3 Rh8 7. g5+ Ke6 >> 8. Re1+ Bxe1 9. Re3+ +-. >> >>3. Qxf7+ Kxh6 4. Rh3+ Bh4 5. Qxb7 and white wins: >> >> a) 5...Nc7 6. dxc5 bxc5 (...Kg7 7. cxb6 axb6 8. Rc3 Rc8 >> 9. Rfc1 Bxf2+ 10. Kxf2 +-) 7. Rxh4+ Qxh4 8. Qc6+ Kg7 >> 9. Qxc7+ Kg8 10. h3 +-. >> >> b) 5...cxd4 6. f4 Nc7 7. Qxe4 Kg7 8. Qe5+ Bf6 9. Rxh8 Kxh8 >> 10. Qh5+ Kg8 11. Qg6+ Kf8 12. g5 +-. >> >> c) 5...Qg5 6. Qxa6 Qxg4 (...Rag8 7. f3 cxd4 8. Qc4 e3 9. Rc1 Rg6 >> 10. Qxd4 Rd8 11. Qe4 +-) 7. f3 exf3 8. Rfxf3 Rae8 9. Qf1 +-. >> >>So black is dead meat after 1...dxe4. Black's only serious alternative is >> >>1....Rh8, leading to the line 1. e4 Rh8 2. Qxf7+ Kxh6 3. Rf3 Rf8 >>4. Qxb7 and now Nb4 appears best for black. I've analyzed a number of >>continuations and have not been able to prove an ironclad win for white >>in all of them, but white definitely has the upper hand and black is >>merely defending. > >I think your analysis is quite convincing ; e4 seems to be the best move and >requires a very deep search . Here some output from Crafty17.10 : > >12 15:51 0.06 1. g4 Qd7 2. g5 Bd8 3. Bh3 Qc7 4. Nf5+ > Kg8 5. Qh6 f6 6. gxf6 Re6 7. Ne7+ Rxe7 > 8. Qg6+ Rg7 9. fxg7 Qxg7 10. Qxg7+ > Kxg7 11. dxc5 bxc5 > 12-> 19:05 0.06 1. g4 Qd7 2. g5 Bd8 3. Bh3 Qc7 4. Nf5+ > Kg8 5. Qh6 f6 6. gxf6 Re6 7. Ne7+ Rxe7 > 8. Qg6+ Rg7 9. fxg7 Qxg7 10. Qxg7+ > Kxg7 11. dxc5 bxc5 > 13 37:59 -- 1. g4 > 13 42:36 -0.48 1. g4 Rh8 2. Qxf7+ Kxh6 3. Qxb7 Nb4 > 4. f4 Rg8 5. g5+ Bxg5 6. fxg5+ Qxg5 > 7. Rf2 Raf8 8. e4 Qg4 9. Rg3 Qd1+ 10. > Rf1 Rxf1+ 11. Bxf1 Rxg3+ 12. hxg3 Qxd4+ > 13 72:19 -0.22 1. e4 dxe4 2. g4 Bc8 3. Qxf7+ Kxh6 > 4. Rh3+ Bh4 5. Rxh4+ Qxh4 6. Qxe8 Kg7 > 7. Qe5+ Kf8 8. Qf4+ Kg8 9. Bxe4 Rb8 > 13 111:18 0.00 1. Nxf7 Qd7 2. Nh6 Kf8 3. Qf3 Ke7 4. > Qf4 Qc7 5. Qf5 Qd7 6. Qf4 > (4) 13-> 137:08 0.00 1. Nxf7 Qd7 2. Nh6 Kf8 3. Qf3 Ke7 4. > Qf4 Qc7 5. Qf5 Qd7 6. Qf4 > (3) 14 141:49 -0.03 1. Nxf7 Qd7 2. Nh6 Kf8 3. Ng4 Bg7 4. > Nh6 Rab8 5. h3 cxd4 6. exd4 Bf6 7. > Nf5 Rbc8 8. Rfc1 > (2) 14 264:24 0.30 1. e4 dxe4 2. g4 Bc8 3. Qxf7+ Kxh6 > 4. Rh3+ Bh4 5. Qh5+ Kg7 6. Rxh4 Rb8 > 7. Bxe4 Qxh4 8. Qxh4 Rxe4 9. Qg5+ Kh7 > 10. Qh5+ Kg7 > > >I didn't want to wait longer and stopped here but I'd expect a fail high on e4 >at ply 15 . > >What is strange to me is that Dr Hyatt has posted that Crafty17.11 sticks to >Nxf7 right from the start until end of ply 14 . This is really a major change to >17.10 and the result seems to be not too good . I think this is a good example to show that "best moves" in EPD test positions are only "best moves" for a certain depth unless a checkmate is found. For instance, a computer of ten years ago would be doing very well to find Nxf7. But upon searching deeper, it seems g4 might be better. After an even deeper search, e4 looks better. I would not be surprised in the least if an even deeper search turned up something else, including one of the previous moves. In short, I think that best moves are valid to some particular ply depth if they have the appropriate evaluation. But until we definitely find a checkmate, there is always a possibly better move -- perhaps hidden by NULL move or some such.
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