Author: Heiner Marxen
Date: 08:34:04 05/15/04
Go up one level in this thread
On May 13, 2004 at 17:31:56, John Merlino wrote: >On May 13, 2004 at 04:08:55, Martin Baumung wrote: > >>On May 12, 2004 at 16:11:59, John Merlino wrote: >> >>>CM_SKR on an AMD 2500 announces mate in 11 in 0:02, and upgrades to mate in 10 >>>after 0:11. >>> >>>Time Depth Score Positions Moves >>>0:00 1/3 4.68 1747 1.Qc7 O-O 2.Rxe7 Rdd8 3.Qxb7 Qxb7 >>> 4.Rxb7 >>>0:00 1/4 4.65 8191 1.Qc7 O-O 2.Rxe7 Rdd8 3.Qxb7 Qc4 >>>0:00 1/5 5.07 19885 1.Qc7 O-O 2.Rxe7 Rdd8 3.f6 Bh6 >>> 4.Qg3+ Kh7 5.Rxb7 >>>0:00 1/5 6.74 36065 1.Rxe7+ Kxe7 2.f6+ Bxf6 3.Qc7+ >>> Ke8 4.Re3+ Kf8 5.Qxd6+ Kg8 6.Qxf6 >>>0:00 1/6 9.86 95561 1.Rxe7+ Kxe7 2.Qc7+ Kf8 3.f6 Bxf6 >>> 4.Qxd6+ Be7 5.Qb8+ Kg7 6.Qe5+ Kh6 >>> 7.Qxh8+ Kg6 8.Qg8+ Kh6 9.Rxf7 >>>0:01 1/7 12.42 549113 1.Rxe7+ Kf8 2.Qc7 Kg8 3.Rxf7 Rh7 >>> 4.Qe7 Qe2 5.Rxg7+ Rxg7 6.Qxe2 >>>0:02 1/8 Mate11 1020395 1.Rxe7+ Kf8 2.Qc7 Kg8 3.Rxf7 Bxd4+ >>> 4.cxd4 Qf1+ 5.Rxf1 Rh7 6.Rf8+ Kxf8 >>> 7.Ne6+ Rxe6 8.fxe6+ Kg8 9.Qc8+ >>> Kg7 10.Qf8+ Kg6 11.Qf6# >>>0:05 1/9 Mate11 2076026 1.Rxe7+ Kf8 2.Qc7 Qe2 3.Ne6+ Kg8 >>> 4.Re8+ Kh7 5.Ng5+ Kh6 6.Nxf7+ Kh7 >>> 7.Ng5+ Kh6 8.Qxd6+ Qe6 9.Qxe6+ >>> Kxg5 10.Qg6+ Kh4 11.Qg3# >>>0:11 1/10 Mate10 4346857 1.Rxe7+ Kf8 2.Qc7 Qe2 3.Ne6+ Kg8 >>> 4.Rxf7 Bxd4+ 5.cxd4 Qd1+ 6.Rf1 >>> Qxd4+ 7.Kh1 Rd7 8.Rxd7 Qg1+ 9.Rxg1 >>> Rh7 10.Qb8# >>>0:25 1/11 Mate10 10426374 1.Rxe7+ Kf8 2.Qc7 Qe2 3.Ne6+ Kg8 >>> 4.Rxf7 Bxd4+ 5.cxd4 Qd1+ 6.Rf1 >>> Qxd4+ 7.Kh1 Rd7 8.Rxd7 Qg1+ 9.Rxg1 >>> Rh7 10.Qb8# >>> >>>jm >> >>Hi John, >> >>actually black's move 1. ..Kf8 is not optimal. Thereafter white can mate black >>within a total of 9 moves only. >> >>1.Re1xe7+ Ke8-f8 2.Qa5-c7 Bg7xd4+ 3.c3xd4 Qb5-e2 4.Nc5-e6+ Qe2xe6 5.f5xe6 Kf8-g7 >>6.Rf3-g3+ Kg7-h6 7.Re7xf7 h5-h4 8.Rf7-f6+ Kh6-h5 9.Qc7-f7# >> >>1. ..Kxe7 is the only move to reach a mate in 10. >> >>Cheers, >> >>Martin > >Correct, although it takes CM_SKR on an AMD 2500 quite some time to see this. >After forcing 1.Rxe7+, The King needs 3:40 to see that Kf8 loses one move faster >than Kxe7. Not a big deal, just interesting.... > >jm According to Chest this actually is a mate in 9: PV: Qc7 Bf6 Rxe7+ Bxe7 Re3 Qf1+ Kxf1 Re6 Qc8+ Bd8 Rxe6+ fxe6 Qd7+ Kf8 Nxe6+ Kg8 Qg7# I didn't ask for a solution tree, but the "refutation table" shows: refu 43: Qc7 Bf6 [ 7-] solu 1: Bxd4+ [ 6+] solu 2: Qf1+ [ 6+] solu 3: Bh6 [ 1+] solu 4: Re6 [ 1+] solu 5: Rg6 [ 1+] solu 6: Qc4 [ 1+] solu 7: Qxc5 [ 1+] solu 8: h4 [ 1+] solu 9: Rg8 [ 1+] solu 10: Rf8 [ 1+] solu 11: Rh7 [ 1+] solu 12: Rhh6 [ 1+] solu 13: Rf6 [ 1+] solu 14: Rdh6 [ 1+] solu 15: f6 [ 1+] solu 16: e6 [ 6+] solu 17: e5 [ 6+] solu 18: b6 [ 1+] solu 19: Bf6 [ 8+] solu 20: Bf8 [ 4+] solu 21: Kf8 [ 2+] solu 22: Be5 [ 6+] solu 23: Rd7 [ 2+] solu 24: Rd8 [ 1+] solu 25: Qb6 [ 1+] solu 26: Qe2 [ 6+] solu 27: Qd3 [ 1+] solu 28: Qa6 [ 1+] solu 29: Qa5 [ 1+] solu 30: Qxb4 [ 1+] solu 31: Qa4 [ 1+] So, Bf6 appears to be the best answer, all other moves result in shorter mates. Since it starts with a quiet move, it is hard to find, of course. [Chest needed 1 hour with 100MB hash on an Athlon 1500+] Cheers, Heiner
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