Hey Guys,
just a very nice game i played and on the analysis it has shown, that i found very nice move, that stockfish didn't even consider and that leads to a faster mate than the one stockfish figured out. Please enjoy!
Look at the analysis after move 22 Qd7. I played the for me pretty logical move Rook takes rook with the Idea of
Ra1 and then Ra8.
Edit: Stockfish suggests the move Qg5 which leads to a mate in 11.
If you allow Stockfish to search deeper than 18 plies it thinks you have forced mate as early as move 21.
You do know that the stockfish on lichess is searching deeper than 18 plies, right? It's 23...
Funny thing, if I open the game and jump to the position after 22...Qd7, Stockfish tells me that 23. Rda1 is a #8 (with 23. Qg5 - I assume your Qd5 is a typo - as the next best move as a #13, not #11).
That's pruning for you.
Thx, I did make a typo! Well, Stockfish is telling me to go either Bg5 or Qg5 :-)
And the most interesting thing is, it only did show up, after I analyzed it.
Stuff like this happens from time to time. Even a modern engine like Stockfish is still far from perfect ... and of course limited by time and hardware.
I'm currently at depth 58, with these moves as top 5:
23. Rda1 #8
23. Rxf8+ #9
23. Bg4 #9
23. Qg5 #10
23. Bb5 #10
So it seems that you found a slightly better mate than Stockfish on your machine, but Stockfish beats both by a small margin on mine. It could very well have been the other way around, too, though.
When I ran Stockfish on your game here on Lichess it only went to 18 plies but I could click the + button to go to infinite depth. I don't know why I get 18 plies by default and you get 23 - maybe the website detects the computer hardware.