Checkmate issue with Chess.com

[Chessnut1071]

The following FEN is copied from Chess.com for a 4-move mate puzzle.

FEN[197] = "r3rb1k/pp2q1n1/2b3QB/2p5/4P3/2NP2R1/PPP3PP/R5K1 w - - 0 1"; // Chess.Com [1. Rf1 Rac8 2. Rxf8 Qxf8 3. Bxg7 Qxg7 4. Qxg7 ==

They give a 4-move solution above. However, I can not find a mate in under 6 moves. For example, after 1. Rf1 ... my engine finds that 1. ... Qg5 stops the mate in 4 and mate in 5. I find a mate in 6 however. Am I missing something or is Chess.com not checking their solutions again. I don't want to make an issue if I'm wrong, so if someone can verify the solution it would be helpful.

[AAce3]

After Bxg7 black can play Kg8, which means mate in 6 rather than in 4.

[Chessnut1071]

After Bxg7 black can play Kg8, which means mate in 6 rather than in 4.

thanks, got the same solution. I can't believe they don't check those solutions before they publish them. I'm thinking they're not using a computer search.

[Ajedrecista]

Hello:

The fun fact is that this position is correctly stored as #6 in the Chest database that I have got.

Code: Select all

FEN: r3rb1k/pp2q1n1/2b3QB/2p5/4P3/2NP2R1/PPP3PP/R5K1 w - - 0 1

ChestUCI:
FEN: r3rb1k/pp2q1n1/2b3QB/2p5/4P3/2NP2R1/PPP3PP/R5K1 w - -   (13+10)
Stellungs-Analyse:  C0/R0/K2/P9/X31   W:11/45
Problem im Clipboard gefunden:  #6; 00:02;
Suche nach Matt in 10 ...  (Hash=64MB)
   6	00:02	   1.172.070	647.194	+M6	Ra1f1
Suche abgeschlossen ...  (Zeit=2.77s)
Matt in 6 gefunden !  (1 Lösung in 00:02)
  6/6	00:02	   1.813.684	655.706	+M6	Ra1f1 Bc6xe4 Bh6xg7+ Bf8xg7 Rg3h3+ Kh8g8 d3xe4 Qe7f6 Rf1xf6 c5c4 Qg6f7+

Regards from Spain.

Ajedrecista.