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Up Topic The Rybka Lounge / Test Positions / Mate in 4
- - By HarshQueen (**) Date 2010-10-30 06:39
Difficult mate in 4!

1K2N2B/p1pR1P1p/1pP1k3/3p2nB/1r3qP1/1N1r4/4p3/4b3 w - - 0 1
Parent - - By Morpheus (****) [pl] Date 2010-11-10 18:46
Yes,, great position.. :evil: :evil:

1. Nd2 d4 2. Ng7+ Ke5 3. Nf5+ Ke6 4. f8=N#
Parent - - By Weirwindle (***) [us] Date 2010-11-10 23:38
It took Rybka 4 15 minutes 20 seconds to find mate in 4.
[Mate in 4]  d=11  1.Nd2 Bxd2 2.Kb7 e1Q 3.f8Q Qxf8 4.Nxc7# (0:15:21) 186039kN
[+53.32]  d=11  1.Nd2 Bxd2 2.Kb7 (0:00:23) 2916kN
[+27.72]  d=11  1.Nd2 Bxd2 2.Kb7 (0:00:23) 2825kN
[+14.92]  d=11  1.Nd2 Bxd2 2.Kb7 (0:00:21) 2518kN
[+8.52]  d=11  1.Nd2 Bxd2 2.Kb7 (0:00:17) 1896kN
[+5.32]  d=11  1.Nd2 Bxd2 2.Kb7 (0:00:14) 1579kN
[+3.72]  d=11  1.Nd2 Bxd2 2.Kb7 (0:00:13) 1485kN
[+2.92]  d=11  1.Nd2 Bxd2 2.Kb7 (0:00:13) 1439kN
[+2.52]  d=11  1.Nd2 Bxd2 2.Kb7 (0:00:13) 1413kN
[+2.47]  d=11  1.Ng7 Ke5 2.Re7 Kd6 3.Nf5 Kxc6 4.f8Q Kb5 5.Qe8 Kc4 6.Be5 Qxe5 7.Rxe5 Kxb3 8.Rxe2 Bc3 9.Re3 Rxe3 10.Nxe3 Rd4 11.Qb5 Bb4 12.Kxc7 Ne4 13.Bf7 Nc3 14.Bxd5 Kb2 15.Qc6 Bc5 16.Qf6 (0:00:10) 1080kN
[+2.37]  d=11  1.Ng7 Ke5 2.Re7 Kd6 3.Nf5 Kxc6 4.f8Q Kb5 5.Qe8 c6 6.Be5 Qxe5 7.Rxe5 Rbxb3 8.Rxe2 Bb4 9.Rc2 Rbc3 10.Rxc3 Rxc3 11.Nd4 Kc4 12.Ne2 Rf3 13.Qxc6 Bc5 14.Qa4 Kd3 15.Nf4 Kd2 16.Nxd5 (0:00:08) 826kN
[+2.25]  d=10  1.Ng7 Ke5 2.Re7 Kd6 3.Nf5 Kxc6 4.f8Q Kb5 5.Qe8 c6 6.Be5 Qxe5 7.Rxe5 Rbxb3 8.Rxe2 Bb4 9.Rc2 Rbc3 10.Rxc3 Rxc3 11.Nd4 Kc4 12.Ne2 Rf3 13.Qxc6 Bc5 14.Qa4 Kd3 15.Nf4 Kd2 16.Nxd5 (0:00:06) 560kN
[+2.25]  d=9  1.Ng7 Ke5 2.Re7 Kd6 3.Nf5 Kxc6 4.f8Q Kb5 5.Qe8 c6 6.Be5 Qxe5 7.Rxe5 Rbxb3 8.Rxe2 Bb4 9.Rc2 Rbc3 10.Rxc3 Rxc3 11.Nd4 Kc4 12.Ne2 Rf3 13.Qxc6 Bc5 14.Qa4 Kd3 15.Nf4 Kd2 16.Nxd5 (0:00:05) 498kN
[+1.47]  d=9  1.Ng7 Ke5 2.Re7 Kd6 3.Nf5 Kxc6 4.f8Q Kb5 5.Qe8 Kc4 6.Be5 Qe4 7.Nbd4 Rxd4 8.Bxd4 c5 9.Bf7 Kd3 10.Rxe4 Nxe4 11.Bxd5 Bg3 12.Nxg3 e1Q 13.Bxe4 Kxd4 14.Nf5 Kc3 15.Qe5 (0:00:01) 185kN
[+0.67]  d=9  1.Ng7 Ke5 2.Re7 Kd6 3.Nf5 Kxc6 4.f8Q Kb5 5.Qe8 Kc4 6.Be5 Qe4 7.Na1 (0:00:01) 143kN
[+0.27]  d=9  1.Ng7 Ke5 2.Re7 Kd6 3.Nf5 Kxc6 4.f8Q Kb5 5.Qe8 Kc4 6.Be5 Qe4 7.Na1 (0:00:01) 130kN
[+0.12]  d=9  1.Ng7 Ke5 2.Re7 Kd6 3.Nf5 Qxf5 4.gxf5 Kxe7 5.f6 Ke6 6.f8Q Kf5 7.Qc8 Ne6 8.f7 (0:00:01) 112kN
[+0.00]  d=9  1.Kb7 Bg3 2.Ng7 Ke5 3.Re7 Kd6 4.Rd7 Ke5 5.Re7 Kd6 6.Rd7 Ke5 7.Re7 Kd6 8.Rd7 Ke5 9.Re7 Kd6 10.Rd7 Ke5 11.Re7 Kd6 12.Rd7 Ke5 13.Re7 Kd6 14.Rd7 Ke5 15.Re7 Kd6 16.Rd7 (0:00:00) 80kN
[+0.00]  d=8  1.Kb7 Bg3 2.Ng7 Ke5 3.Re7 Kd6 4.Rd7 Ke5 5.Re7 Kd6 6.Rd7 Ke5 7.Re7 Kd6 8.Rd7 Ke5 9.Re7 Kd6 10.Rd7 Ke5 11.Re7 Kd6 12.Rd7 Ke5 13.Re7 Kd6 14.Rd7 Ke5 15.Re7 Kd6 16.Rd7 (0:00:00) 41kN
[+0.00]  d=7  1.Kb7 Bg3 2.Ng7 Ke5 3.Re7 Kd6 4.Rd7 Ke5 5.Re7 Kd6 6.Rd7 Ke5 7.Re7 Kd6 8.Rd7 Ke5 9.Re7 Kd6 10.Rd7 Ke5 11.Re7 Kd6 12.Rd7 Ke5 13.Re7 Kd6 14.Rd7 Ke5 15.Re7 Kd6 16.Rd7 (0:00:00) 17kN

It took Rybka 1.1 0 Minutes 1 seconds to find mate in 4. LOL talk about a downgrade.
[Mate in 4]  d=7  1.Nd2 Bxd2 2.Kb7 Qf6 3.Bxf6 (0:00:01) 39kN
[+0.00]  d=7  1.Nxc7 Qxc7 2.Kxc7 Bg3 3.Kd8 Rf3 4.Re7 Kd6 5.c7 Nxf7 6.Bxf7 Rxf7 7.c8N Kc6 (0:00:00) 13kN
[+0.00]  d=6  1.Nxc7 Qxc7 2.Kxc7 Bg3 3.Kd8 Rf3 4.Re7 Kd6 5.c7 Nxf7 6.Bxf7 Rxf7 7.c8N Kc6 (0:00:00) 5kN
[+0.00]  d=5  1.Nxc7 Qxc7 2.Kxc7 Bg3 3.Kd8 Rf3 4.Re7 Kd6 5.c7 Nxf7 6.Bxf7 Rxf7 (0:00:00) 1kN
[+0.00]  d=4  1.Nxc7 Qxc7 2.Kxc7 Bg3 3.Kd8 Rf3 (0:00:00) 1kN
[+0.00]  d=3  1.Nxc7 Qxc7 2.Kxc7 Bg3 3.Kd8 (0:00:00) 0kN
[+0.00]  d=2  1.Nxc7 (0:00:00) 0kN
Parent - - By dcorbit (***) [us] Date 2010-11-11 22:47
Both Ng7 and Nd2 win easily.
Both Rybka versions easily win the game.

If you want to solve a short mate, the best tool for the job is a mate solver like Chest.

If you want to win the game, Rybka 4 will dance a jig on top of Rybka 1.1's head.
Parent - - By Weirwindle (***) [us] Date 2010-11-12 19:24
I already know this dcorbit. I'm not new to rybka, i was just contrasting the search methods between previous versions of Rybka.
Rybka 4 being especially wonderful do to its knowledge base yet still trying to grasp these difficult mate solutions.
Parent - By dcorbit (***) [us] Date 2010-11-12 21:22
My reply was intended to show that the Rybka 4 search is clearly better than the Rybka 1 search and that the Rybka 4 search is not defective.  Since Rybka 4's move choices easily win the game, and since a chess playing engine's goal is to win the game, there is nothing wrong with the move choices of Rybka 4 in this instance.  It might be nice to have a "mate finder" mode Rybka, like the "Win finder" mode Rybka.  This engine would be a mate proof search engine like Chest.  I see that as an enhancment to the product line for those persons (such as myself) who enjoy mate search proofs and for which a mate in 4 is in some sense better than a mate in 40.  But if such a change would make a chess playing engine weaker then I am opposed to putting the change into the chess engine.
- - By HarshQueen (**) Date 2010-11-13 09:01 Edited 2010-11-13 09:03
Deep Rybka 4 can't see it...

Mate in 4.

5R2/2K5/1pP5/4k2p/3pp3/2p4N/B4N1b/n1R1B2b w - - 0 1


Analysis by Deep Rybka 4 w32:

1.Nxh1 Nb3 2.Bxb3 h4 3.Bxh4 d3 4.Kxb6 Kd4 5.Bf6+ Be5 6.Rd8+
  +-  (17.73)   Depth: 6   00:00:00  37kN
1.Nxh1 Nb3 2.Bxb3 h4 3.Bxh4 d3 4.Kxb6 Kd4 5.Bf6+ Ke3 6.Bg5+ Kd4 7.Rd8+ Ke5 8.Rd5+ Ke6 9.Rxd3+
  +-  (19.99)   Depth: 7   00:00:00  51kN
1.Nxh1 e3 2.Kxb6 Nb3 3.Bxb3 Ke4 4.Ng5+ Ke5 5.Nf3+ Ke4 6.Ng3+ Bxg3 7.Bxg3 e2 8.Ng5+ Ke3 9.Rf3+ Kd2 10.Bf4#
  +-  (#10)   Depth: 8   00:00:01  280kN
1.Nxh1 h4 2.Kxb6 e3 3.Bxh4 c2 4.c7 Ke4 5.c8Q Bc7+ 6.Qxc7 Kd3 7.Rxa1 Kd2 8.Be1+ Ke2 9.Qxc2#
  +-  (#9)   Depth: 9   00:00:07  1508kN
1.Nxh1 h4 2.Kxb6[] e3 3.Bxh4[] c2 4.c7 Ke4 5.c8Q Bc7+ 6.Qxc7 Kd3 7.Qc4+ Kd2 8.Qxd4+ Kxc1 9.Rf1#
  +-  (#9)   Depth: 10   00:00:08  1685kN
1.Nxh1 h4 2.Kxb6[] e3 3.Bxh4[] c2 4.c7 Ke4 5.c8Q Bc7+ 6.Qxc7 Kd3 7.Qc4+ Kd2 8.Qxd4+ Kxc1 9.Rf1#
  +-  (#9)   Depth: 11   00:00:11  2222kN

5R2/2K5/1pP5/4k2p/3pp3/2p4N/B4N1b/n1R1B2b w - - 0 1


Analysis by ChestUCI Ver.5.1:

1.Rxc3 d3 2.Rxd3 Nb3 3.Bxb3 h4 4.Ng4#
  +-  (#4)   Depth: 4/4   00:00:00
Parent - - By Christian Packi (****) [de] Date 2010-11-13 15:49
What is the difference between mate in 9 and mate in 4?
Parent - - By Fulcrum2000 (****) [nl] Date 2010-11-13 16:47
5 moves :twisted:
Parent - By Christian Packi (****) [de] Date 2010-11-13 17:00
:wink:
Up Topic The Rybka Lounge / Test Positions / Mate in 4

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