mmt Vs. Ovyron (G4 D5 BG2)

[Zenmastur]

SF sees a mate!

Yeah, I think once you can see a mate with programs, it's enough. I resign.

Thanks, guys. Can you please post the mate it sees?
That would be a fitting end to the game.

Here is the mate I had from this position:

[d]5nk1/6p1/2p5/5p2/1P1P3P/2r3q1/5N2/3QNK2 b - - 1 1

Code: Select all

( [Stockfish 11 64 POPCNT] 75:M36 1...Ng6 2.d5 Nf4 3.dxc6 Rxc6 4.Qf3 Qxf3 5.Nxf3 Rc1+ 6.Ne1 Kh7 7.b5 Rb1 8.b6 Rxb6 9.Nd1 Rb1 10.Nc3 Rc1 11.Na2 Ra1 12.Nb4 Rb1 13.Nc2 Nd3 14.Ke2 Rxe1+ 15.Kxd3 Re4 16.Ne3 Kg6 17.h5+ Kg5 18.Nf1 Re1 19.Ne3 Rxe3+ 20.Kxe3 Kg4 21.Kf2 Kxh5 22.Kg3 g5 23.Kf3 f4 24.Ke4 Kg4 25.Kd3 Kg3 26.Kc4 f3 27.Kd5 f2 28.Kd6 g4 29.Ke5 Kh4 30.Kd5 g3 31.Kd4 g2 32.Kc3 g1=Q 33.Kc2 f1=Q 34.Kc3 Qc5+ 35.Kb2 Qfc1+ 36.Kb3 Q5a3# )

Stockfish-dev sees a mate in 34: Ng6 2. d5 Nf4 3. d6 Nh3 4. Ned3 Qxd6 5. Qe1 Nxf2 6. Nxf2 Rc4 7. Qe8+ Kh7 8. Qh5+ Qh6 9. Qxf5+ Qg6 10. Qf3 Rxb4 11. Ke2 Rb2+ 12. Kf1 Rxf2+ 13. Kxf2 Qf6 14. Qxf6 gxf6 15. Kg2 c5 16. Kf3 Kg6 17. Ke3 Kh5 18. Ke4 Kxh4 19. Kf4 c4 20. Kf3 f5 21. Kf4 c3 22. Ke3 f4+ 23. Ke2 Kg5 24. Kd3 f3 25. Kxc3 f2 26. Kd4 f1=Q 27. Kc5 Qf4 28. Kb5 Qd4 29. Kc6 Qb4 30. Kd7 Qc5 31. Ke6 Kg6 32. Kd7 Kf6 33. Kd8 Ke6 34. Ke8 Qe7#

I'm not at all surprised. This was a particularly easy one to find and I didn't let the search run after it put the pound sign at the end of the mate. I'll dutifully record your line at the end of the game.

Regards,

Zenmastur

[Ovyron]

I wonder if mmt would have continued playing if I went for Ng6.

[jp]

Stockfish-dev has failed to demonstrate a solution.

info depth 91 seldepth 102 multipv 1 score cp 359 nodes 6332175484277

Stockfish-dev seems to be doing a bit better here

info depth 84 seldepth 105 multipv 1 score cp 547 nodes 12623729511469

It then kept on failing high up to +8.96 when I stopped the search.

Louis & Drew, if you are able to compile the source code, can you please modify the SF code as below (to turn off the 50-move rule), recompile and try again ( 5B2/1n6/1k6/3K4/B7/8/8/8 w - - 0 1 )?

With only 5 pieces, I think it goes to high depths quickly (but only when the 50-move rule is turned off). But my prediction is it'll need to get to depths >=180 before it finds the win. If that sounds like it'll take too long, here's the position after I've fed it the first 28 plies of the solution, when according to my prediction it might need "only" depths >=120:

8/8/6k1/2K3n1/7B/1B6/8/8 w - - 0 1

position.cpp

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  if (st->rule50 > 99 && !is_mate())
      return true;  

This seems both the easiest and the safest change to make. Just turn off the rule by changing 99 to 10000, or if we want the rule in modified form to some suitable number.