Author: Heiner Marxen
Date: 18:07:46 05/13/01
Go up one level in this thread
On May 13, 2001 at 11:42:22, leonid wrote:
>Hello!
>
>If you want to solve one easy mate then this is the right one:
>
>[D]1BqQ4/nB6/1p2NQ2/kbbrNRRK/1p2NQ2/nB6/1BqQ4/8 w - -
>
>Please indicate your result.
>
>This night I wanted to solve few positions on Mate 2 but could not find how to
>say exact number of moves to search and could not see the time. If you will
>solve this position on Mate 2.0 (like me from Hiarcs package), or from some
>other version of Mate, please say your time. If you happened to solve recently
>on Mate some other mate positions, please put here, at least, one of them. Ideal
>will be mate between 6 and 9 moves. Don't forget to mention hash of program and
>speed of your computer.
>
>Thanks,
>Leonid.
Chest on a K7/600 with 350 MB hash (100 MB would have been enough this time)
needs 589 seconds (10 minutes) to come up with 2 ley moves for "mate in 7".
Since both are not checks, I give some more variants, not just the PVs:
N4xc5 Be8+ Kh6 Qxd2 Qxb6+ Kxb6 Nc4+ Nxc4 Bc7+ Qxc7 Qxc7+ Kb5 Ba6#
Be2+ Kh6 Bc4 Qxb6+ Kxb6 Nc7+ Ka5 Qa6+ Bxa6 Qfxb4#
Nc4 Nxc4+ Bxc4 Qxb6+ Kxb6 Nc7+ Ka5 Qa6+ Bxa6 Qfxb4#
Q8xc5 Qxb6+ Kxb6 Nxc5+ Bc6 Ned7+ Rxd7 Qfxb4+ N3b5 Qa5#
Qc3 Nc4+ Bxc4 Qxb6+ Kxb6 Bc7+ Qxc7 Qxc7+ Kb5 Ba6#
Qd1+ Bxd1 Be2+ Qxe2 N7b5 Qxb5+ Kxb5 Nd4+ =*= Qfxb6#
Qxd2 Qxb6+ Kxb6 Nc4+ Bxc4 Bc7+ Qxc7 Qxc7+ Kb5 Ba6#
Rd4 Qxb6+ Kxb6 Nc4+ Bxc4 Nd8+ Ka5 Na4+ Q2xf5 Qb6#
Rxd2 Qxb6+ Kxb6 Nc4+ Bxc4 Nd8+ Ka5 Na4+ Q2xf5 Qb6#
Bc4 Qxb6+ Kxb6 Nc7+ Ka5 Qa6+ Bxa6 Qfxb4#
Q2xc5 Nxc5 Be2+ Qxe2 Nc4 Nxc4+ Kb5 Qfxb6#
Qc4 Nxc4+ Bxc4 Qxb4+ Kxb4 Bc3+ Kb5 Ba4#
Qe4 Nc4+ Bxc4 Qxb4+ Kxb4 Bc3+ Kb5 Ba4#
Nc6 Nxc6+ =*= Qfxb4#
Qxb3 Nxb3+ Ka4 Qfxb4#
-*- Qfxb4#
N6xc5 Be2+ Ng4 Bxg4+ Kh6 Nc4 Qf1 Nb5 Qa1+ Nba3 Qxa3+ Kb5 Qaxb4#
Be8+ Ng6 Bxg6+ Kh6 Nc4 Qf1 Nb5 Qa1+ Nba3 Qxa3+ Kb5 Qaxb4#
Nc6 Nxc6+ Bxc6 Qxb6+ Kxb6 Qxb4+ Nb5 Ba7+ Kxa7 Qa5#
Q8xc5 Nxc5 Qd1+ Qxd1 Bc6 Nxc6+ Nxc6 Na4 Kb5 Rxd5#
Qc7 Nc6+ Bxc6 Qxb4+ Kxb4 Bc3+ Qxc3 Qxc3+ Kb5 Ba6#
Qd1+ Bxd1 Be8+ Kh6 Bc6 Nb3+ Kb5 Nd6+ =*= Qfxb4#
Qxd8 Qxb4+ Kxb4 Nc6+ Bxc6 Bc3+ Qxc3 Qxc3+ Kb5 Ba6#
Rd6 Qxb4+ Kxb4 Nc6+ Bxc6 Nd2+ Ka5 Na6+ Q2xf5 Qb4#
Rxd8 Qxb4+ Kxb4 Nc6+ Bxc6 Nd2+ Ka5 Qb4+ Kxb4 Na6#
Bc6 Qxb4+ Kxb4 Nc3+ Ka5 Qa4+ Bxa4 Qfxb6#
Q2xc5 Nxc5 Be2+ Qxe2 Nc4 Nxc4+ Kb5 Qfxb6#
Qc6 Nxc6+ Bxc6 Qxb6+ Kxb6 Bc7+ Kb5 Ba6#
Qe6 Nc6+ Bxc6 Qxb6+ Kxb6 Bc7+ Kb5 Ba6#
Nc4 Nxc4+ =*= Qfxb6#
Qxb7 Nxb7+ Ka6 Qfxb6#
-*- Qfxb6#
They are completely symetric (line 1 has no symetric counterpart).
The effective branching factor of Chest is well above 10:
depth seconds
# 1 0.00 0.87 1- 0
# 2 0.00 1.00 1- 0
# 3 0.03 0.97 88- 0
# 4 0.28 1.06 1103- 0
# 5 2.98 1.17 11673- 0
# 6 34.17 1.29 139710- 0
# 7 588.01 1.38 2086866- 69
Also, the hash table did not contribute very much (factor 1.38).
Cheers,
Heiner
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