Mate with bishops

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thewhip
Posts: 32
Joined: Thu Sep 20, 2018 10:50 pm
Full name: Juan Garcia

Mate with bishops

Post by thewhip »

[fen]1R6/1B2P3/2b4B/8/8/3K4/pr6/1k6 w - - 0 1[/fen]

Interesting endgame to which not all engines find the solution easily. Some engines find the key in a few seconds and others with several minutes do not find it. The approach is attractive because of the way the bishops are locking up the king.
I think it is a good measure to know how good it is in an endgame.
By the way, this one belongs to
A. V. Evreinov, 1968
who won a third prize in a competition.
In the database we figure that it is a mate in 8. I only got the least mate in 15 moves.
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Ajedrecista
Posts: 2172
Joined: Wed Jul 13, 2011 9:04 pm
Location: Madrid, Spain.

Re: Mate with bishops.

Post by Ajedrecista »

Hello Juan:
thewhip wrote: ↑Sun Oct 03, 2021 9:27 pm [fen]1R6/1B2P3/2b4B/8/8/3K4/pr6/1k6 w - - 0 1[/fen]

Interesting endgame to which not all engines find the solution easily. Some engines find the key in a few seconds and others with several minutes do not find it. The approach is attractive because of the way the bishops are locking up the king.
I think it is a good measure to know how good it is in an endgame.
By the way, this one belongs to
A. V. Evreinov, 1968
who won a third prize in a competition.
In the database we figure that it is a mate in 8. I only got the least mate in 15 moves.
Very interesting problem! The intended solution is very, very nice and can be found at YACPDB (Yet Another Chess Problem Database):

https://yacpdb.org/#285252

More info about the author can be found at Arves website.

Regarding maximizing DTM, I also reached checkmate in 15 and no shorter checkmates mixing short analysis by SF 14 and Chest 5.2. It does not mean that 15 is the true shortest DTM, it means that I did not found anything shorter, but I spent few time on my analysis. My mainline starts:

[pgn][Result="1-0"]
[Setup "1"]
[FEN "1R6/1B2P3/2b4B/8/8/3K4/pr6/1k6 w - - 0 1"]
1. e8=Q Rb3+ 2. Kc4 Rc3+ 3. Kb4 Bxe8 4. Be4+ Kb2 5. Bg7 1-0[/pgn]

And then Chest is able to find checkmate in 10 or less in few minutes:

Code: Select all

FEN: 1R2b3/6B1/8/8/1K2B3/2r5/pk6/8 b - - 3 5

ChestUCI:
FEN: 1R2b3/6B1/8/8/1K2B3/2r5/pk6/8 b - -   (4+4)
Stellungs-Analyse:  S:3/13
Suche nach Matt in -10 ...  (Hash=1024MB)
Suche abgeschlossen ...  (Zeit=152.60s)
Matt in -10 gefunden !  (26 Lösungen in 02:32)
  1/10	02:32	 106.042.183	694.880	-M1	Kb2a1 Bg7xc3+
  6/10	02:32	 106.042.183	694.880	-M6	Be8g6 Be4xg6 a2a1Q Bg7xc3+ Kb2c1 Bc3xa1 Kc1d1 Rb8e8 Kd1c1 Re8e1+ Kc1d2 Ba1c3+
  6/10	02:32	 106.042.183	694.880	-M6	Be8g6 Bg7xc3+ Kb2c1 Be4xg6 a2a1Q Bc3xa1 Kc1d1 Rb8e8 Kd1c1 Re8e1+ Kc1d2 Ba1c3+
  6/10	02:32	 106.042.183	694.880	-M6	a2a1B Rb8xe8 Kb2c1 Bg7xc3 Ba1b2 Bc3xb2+ Kc1d1 Be4f5 Kd1d2 Bb2c3+ Kd2d1 Re8e1+
  6/10	02:32	 106.042.183	694.880	-M6	a2a1B Bg7xc3+ Kb2c1 Rb8xe8 Ba1b2 Bc3xb2+ Kc1d1 Be4f5 Kd1d2 Bb2c3+ Kd2d1 Re8e1+
  6/10	02:32	 106.042.183	694.880	-M6	a2a1N Bg7xc3+ Kb2c1 Rb8xe8 Na1c2+ Be4xc2 Kc1xc2 Re8e3 Kc2c1 Kb4b3 Kc1d1 Re3e1+
  7/10	02:32	 106.042.183	694.880	-M7	Be8f7 Rb8h8 Kb2c1 Bg7xc3 Bf7b3 Kb4xb3 a2a1N+ Kb3c4 Kc1d1 Be4f3+ Kd1c1 Rh8h1+ Kc1c2 Bf3e4+
  7/10	02:32	 106.042.183	694.880	-M7	Be8f7 Bg7xc3+ Kb2c1 Rb8h8 Bf7b3 Kb4xb3 a2a1N+ Kb3c4 Kc1d1 Be4f3+ Kd1c1 Rh8h1+ Kc1c2 Bf3e4+
  7/10	02:32	 106.042.183	694.880	-M7	Be8b5 Rb8a8 Bb5c6 Bg7xc3+ Kb2c1 Be4xc6 Kc1c2 Bc6e4+ Kc2c1 Be4f5 Kc1d1 Ra8e8 a2a1Q Re8e1+
  7/10	02:32	 106.042.183	694.880	-M7	Be8b5 Bg7xc3+ Kb2c1 Rb8a8 Bb5c6 Be4xc6 Kc1c2 Bc6e4+ Kc2c1 Be4f5 Kc1d1 Ra8e8 a2a1Q Re8e1+
  7/10	02:32	 106.042.183	694.880	-M7	Be8c6 Be4xc6 a2a1Q Bg7xc3+ Kb2c2 Bc3xa1 Kc2d2 Rb8e8 Kd2c2 Ba1c3 Kc2c1 Re8e1+ Kc1c2 Bc6e4+
  7/10	02:32	 106.042.183	694.880	-M7	Be8c6 Bg7xc3+ Kb2c1 Be4xc6 a2a1Q Bc3xa1 Kc1d1 Rb8e8 Kd1c1 Re8e1+ Kc1c2 Bc6e4+ Kc2d2 Ba1c3+
  8/10	02:32	 106.042.183	694.880	-M8	Be8h5 Rb8a8 Bh5f7 Bg7xc3+ Kb2c1 Ra8h8 Bf7b3 Kb4xb3 a2a1N+ Kb3c4 Kc1d1 Be4f3+ Kd1c1 Rh8h1+ Kc1c2 Bf3e4+
  8/10	02:32	 106.042.183	694.880	-M8	Be8h5 Rb8d8 Bh5g4 Bg7xc3+ Kb2c1 Rd8d4 a2a1Q Bc3xa1 Bg4f3 Be4xf3 Kc1c2 Ba1c3 Kc2c1 Kb4b3 Kc1b1 Rd4d1+
  8/10	02:32	 106.042.183	694.880	-M8	Be8h5 Bg7xc3+ Kb2c1 Rb8d8 Bh5g4 Rd8d4 a2a1Q Bc3xa1 Bg4f3 Be4xf3 Kc1c2 Ba1c3 Kc2c1 Kb4b3 Kc1b1 Rd4d1+
  8/10	02:32	 106.042.183	694.880	-M8	Be8d7 Rb8h8 Kb2c1 Bg7xc3 Bd7a4 Rh8h1+ Ba4d1 Be4f3 a2a1Q Rh1xd1+ Kc1c2 Rd1xa1 Kc2d3 Ra1e1 Kd3c2 Bf3e4+
  8/10	02:32	 106.042.183	694.880	-M8	Be8d7 Rb8g8 Bd7a4 Bg7xc3+ Kb2c1 Rg8g1+ Ba4d1 Be4f3 a2a1Q Rg1xd1+ Kc1c2 Rd1xa1 Kc2d3 Ra1e1 Kd3c2 Bf3e4+
  8/10	02:32	 106.042.183	694.880	-M8	Be8d7 Rb8f8 Kb2c1 Bg7xc3 Bd7a4 Rf8f1+ Ba4d1 Be4f3 a2a1Q Rf1xd1+ Kc1c2 Rd1xa1 Kc2d3 Ra1e1 Kd3c2 Bf3e4+
  8/10	02:32	 106.042.183	694.880	-M8	Be8d7 Bg7xc3+ Kb2c1 Rb8f8 Bd7a4 Rf8f1+ Ba4d1 Be4f3 a2a1Q Rf1xd1+ Kc1c2 Rd1xa1 Kc2d3 Ra1e1 Kd3c2 Bf3e4+
  8/10	02:33	 106.042.183	694.880	-M8	a2a1R Bg7xc3+ Kb2c1 Rb8xe8 Ra1a2 Be4f5 Ra2d2 Bc3xd2+ Kc1xd2 Bf5g6 Kd2c1 Kb4c3 Kc1d1 Bg6c2+ Kd1c1 Re8e1+
  9/10	02:33	 106.042.183	694.880	-M9	Be8a4 Rb8f8 a2a1Q Bg7xc3+ Kb2c1 Rf8f2 Qa1b1+ Be4xb1 Ba4b5 Bb1c2 Bb5c4 Bc3d4 Bc4d3 Bd4e3+ Kc1b2 Bc2xd3+ Kb2a1 Be3d4+
  9/10	02:33	 106.042.183	694.880	-M9	Be8a4 Rb8d8 a2a1Q Bg7xc3+ Kb2c1 Bc3xa1 Ba4d7 Ba1c3 Bd7b5 Be4d3 Bb5c6 Rd8f8 Bc6g2 Rf8f7 Bg2h3 Rf7a7 Bh3g2 Ra7a1+
  9/10	02:33	 106.042.183	694.880	-M9	Be8a4 Kb4xa4+ Kb2c1 Bg7xc3 Kc1d1 Be4f3+ Kd1c2 Bc3a1 Kc2d3 Rb8e8 Kd3d2 Bf3g4 Kd2c2 Re8d8 Kc2c1 Ka4b3 Kc1b1 Rd8d1+
  9/10	02:33	 106.042.183	694.880	-M9	Be8a4 Bg7xc3+ Kb2c1 Rb8d8 a2a1Q Bc3xa1 Ba4d7 Ba1c3 Bd7b5 Be4d3 Bb5c6 Rd8f8 Bc6g2 Rf8f7 Bg2h3 Rf7a7 Bh3g2 Ra7a1+
 10/10	02:33	 106.042.183	694.880	-M10	Kb2c1 Bg7xc3 a2a1Q Bc3xa1 Kc1d2 Ba1c3+ Kd2e2 Rb8xe8 Ke2e3 Bc3d2+ Ke3e2 Bd2f4 Ke2e1 Bf4g3+ Ke1d1 Kb4c3 Kd1c1 Bg3f4+ Kc1d1 Be4f3+
 10/10	02:33	 106.042.183	694.880	-M10	a2a1Q Bg7xc3+ Kb2c1 Bc3xa1 Kc1d2 Ba1c3+ Kd2e2 Rb8xe8 Ke2e3 Bc3d2+ Ke3e2 Bd2f4 Ke2e1 Bf4g3+ Ke1d1 Kb4c3 Kd1c1 Bg3f4+ Kc1d1 Be4f3+
Does your solution start in the same way than mine? Other analysis are welcome.

Regards from Spain.

Ajedrecista.
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Jouni
Posts: 3782
Joined: Wed Mar 08, 2006 8:15 pm
Full name: Jouni Uski

Re: Mate with bishops

Post by Jouni »

Analysis by Stockfish 230921:

1. +- (#15): 1.e8Q Rb3+ 2.Kc4 Rc3+ 3.Kb4 Bxe8 4.Be4+ Kb2 5.Bg7 Kc1 6.Bxc3 a1Q 7.Bxa1 Kd2 8.Rxe8 Ke3 9.Bb2 Kf4 10.Bc1+ Kg3 11.Rf8 Kh4 12.Rg8 Kh5 13.Bf5 Kh4 14.Bf4 Kh5 15.Rh8#
2. +- (#21): 1.e8R Rb3+ 2.Kc4 Rxb7 3.Rxb7+ Bxb7 4.Bg7 a1Q 5.Re1+ Kc2 6.Bxa1 Bf3 7.Bc3 Bh5 8.Rh1 Bf7+ 9.Kd4 Be6 10.Rh2+ Kb3 11.Rb2+ Ka3 12.Rb4 Bb3 13.Bd2 Kb2 14.Kd3 Ka2 15.Kc3 Bd5 16.Bc1 Bc6 17.Bb2 Kb1 18.Rb3 Bd5 19.Ra3 Ba2 20.Ra6 Bg8 21.Ra1#
Jouni
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