I was analyzing a game on chess.com and it showed me that, in the below scenario, it is better to promote to a rook instead of promoting to a queen. It also shows that it has a mate in 6 with the queen, but it also a mate in 4.

I am not sure why chess.com thinks it is mate in 6 and why the rook move is better. I am only ~1200 so I could be missing something obvious. Do you have any ideas?

The game can be seen below, or here on chess.com.

Chess.com analysis

[fen "2k3r1/ppp4P/3rp1Q1/8/3P4/4q3/PPP5/1K1R2R1 w - - 0 1"]
1. d4 d5 Bf4 Nc6 Nf3 Bf5 e3 Nf6 Bd3 Bg6 Nc3 e6 Ne5 Be7 h4 Nxe5 Bxe5 Qd7 g4 Bxd3 Qxd3 O-O-O g5 Ne4 Nxe4 dxe4 Qxe4 Bd6 Bxg7 Rhg8 Bf6 Be7 Bxe7 Qxe7 O-O-O Qd6 Qxh7 Qa6 Kb1 Qd6 Qxf7 Rgf8 Qh5 Rxf2 g6 Rff8 g7 Rg8 Rhg1 Rd7 Qh8 Rdd8 Qh7 Qd5 h5 Qf3 h6 Qxe3 Qg6 Rd6 h7 Rgd8 g8=Q Rxg8 hxg8=Q+ Rd8 Qxd8+ Kxd8 Qh7 Qc1+ Rxc1 c5 Rg8#
  • 2
    Seems like the analysis engine prefers to throw away less material, but promoting to a queen and exchanging it for the rook on d8 leads to the same mate. Commented Mar 29, 2021 at 11:33
  • Stockfish engine depth issues. More time, higher depth it will see better.
    – SmallChess
    Commented Mar 29, 2021 at 11:45
  • @MaciejStachowski The engine line 34. Q6e8 also attempts to sacrifice a queen for the rook and if it had the clear choice between #6 and #4, the engine would pick the #4 no matter the material. But it just doesn't see the #4 yet - likely unfortunate pruning at work (which will be fixed by going to higher depths as SmallChess notes).
    – Annatar
    Commented Mar 29, 2021 at 12:55

2 Answers 2


There's no reason why the rook promotion is better. Don't listen to engines in positions where there's such a big imbalance


Chess engines prefer to checkmate you as soon as they can, and if they can checkmate you in 10 moves, they look if they can also checkmate you in 9 moves. That's also why chess.com thinks rook promotion is better, because it saw a sooner mate. But if you see a mate in 3 and don't see the mate in 1, just play the mate in 3

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