Moderately hard mate in 12

[Eelco de Groot]

Stockfish's search almost explodes here. So your engine may be able to beat Stockfish here finding the way to (minus) Mate in 11 moves after Qxc4 ,12 after Bc3 (or maybe even a bit shorter? Probably not), at the end of a Grob attack where White gets punished mercilessly. SF almost latest dev version, needed 17 minutes, on one thread.


[pgn]
[Event "Analysis Grob attack 15.Nh2"]
[Site "Rick's Café Américain"]
[Date "2022.09.15"]
[Round "?"]
[White "Rebel 15.1 'Casablanca'"]
[Black "Blue Marlin 14.9a"]
[Result "0-1"]

1. g4 d5 2. c4 d4 3. Bg2 c6 4. g5 h6 5. h4 hxg5 6. hxg5
Rxh1 7. Bxh1 Qa5 8. Nf3 Na6 9. Nxd4 Qxg5 10. Nf3 Qh5
11. Bg2 e5 12. Nc3 f6 {White out of book} 13. Ne4 Qg4
14. Ng3 e4 15. Nh2 Qh4 16. Nhf1 f5 17. d4 Bd7 18. a3 O-O-O
19. Qd2 g6 20. d5 Be7 21. Qd4 Nf6 22. d6 Bf8 23. Rb1 c5
24. Qd2 Ne8 25. b4 Bxd6 26. b5 Nac7 27. Qa5 Kb8 28. b6 axb6
29. Rxb6 Bc6 30. Rxc6 bxc6 31. Nxe4 fxe4 32. Qb6+ Kc8
33. Qxc6 Nf6 34. Nd2 Be5 35. e3 Bc3 36. Kd1 Qg4+ 37. Kc2
Bxd2 38. Bxd2 Qxg2 39. Qxf6 Qf1 40. Bc3 Qxc4 {Mate in 12
moves} 0-1
[/pgn]




[fen]2kr4/2n5/5Qp1/2p5/2P1p3/P1B1P3/2K2P2/5q2 b - -[/fen]
After 40. Bc3, Black mates in 12 moves

[peter]

[fen]2kr4/2n5/5Qp1/2p5/2P1p3/P1B1P3/2K2P2/5q2 b - -[/fen]
After 40. Bc3, Black mates in 12 moves

Hi Eelco!

SlowChess excels on 30 threads of 16x3.5GHz, 8G hash, Syzygy Probe Depth set to max. (no probe limit UCI option)

2kr4/2n5/5Qp1/2p5/2P1p3/P1B1P3/2K2P2/5q2 b - - 0 1

Analysis by SlowChess Blitz 2.9 avx2:

1...Dxc4 2.Dxg6 Kb7 3.a4 Td3 4.Dg7 Da2+ 5.Kc1 De2 6.Dxc7+ Kxc7 7.La5+ Kc6
Black is clearly winning: -+ (-15.16) Depth: 10/20 00:00:00
...
1...Dxc4 2.f3 De2+ 3.Kb3 c4+ 4.Kb4 Sd5+ 5.Kb5 Sxf6 6.Lxf6 c3+ 7.Kb4 c2 8.Lb2 exf3 9.Lc1 Td3 10.Kc5 f2 11.Kc4 f1D
Black is clearly winning: -+ (-31.17) Depth: 15/31 00:00:00 12068kN, tb=7810
1...Dxc4 2.f3 De2+ 3.Kb3 c4+ 4.Kb4 Sd5+ 5.Kb5 Sxf6 6.Lxf6 c3+ 7.Kb4 c2 8.Lb2 exf3 9.Lc1 Td3 10.Kc5 f2 11.Kc4 f1D
Black mates: -+ (-#22 ++) Depth: 16/31 00:00:00 12130kN, tb=7952
...
Black mates: -+ (-#17) Depth: 19/33 00:00:01 15520kN, tb=13148
1...Dxc4 2.Kc1 Df1+ 3.Kc2 De2+ 4.Kb3 c4+ 5.Kb4 Sd5+ 6.Kc5 Sxf6 7.Lxf6 Dh5+ 8.Kb4 Td5 9.f3 Tb5+ 10.Kc3 Dh2 11.Le7 Db2+ 12.Kxc4 Db3+ 13.Kd4 Dd3#
Black mates: -+ (-#13) Depth: 20/36 00:00:01 37143kN, tb=64073
...
1...Dxc4 2.a4 De2+ 3.Kb3 c4+ 4.Ka3 Dc2 5.Dxd8+ Kxd8 6.Kb4 Db3+ 7.Kc5 Dxc3 8.a5 Dd3 9.a6 c3 10.a7 Sa8 11.Kb4 c2 12.f4 c1D 13.f5 Dca3#
Black mates: -+ (-#13) Depth: 24/36 00:00:02 51727kN, tb=102746
1...Dxc4 2.a4 De2+ 3.Kb3 c4+ 4.Ka3 Dc2 5.Dxd8+ Kxd8 6.Kb4 Kd7 7.Kxc4 Kc6 8.Kd4 Kd6 9.Kc4 Sd5 10.Kb5 Db3+ 11.Lb4+ Dxb4+ 12.Ka6 Db6#
Black mates: -+ (-#12) Depth: 25/37 00:00:04 96568kN, tb=214183
...
1...Dxc4 2.a4 De2+ 3.Kb3 c4+ 4.Ka3 Dc2 5.Dxd8+ Kxd8 6.Kb4 Kd7 7.Kxc4 Kc6 8.Kd4 Kd6 9.Kc4 Sd5 10.Kb5 Db3+ 11.Lb4+ Dxb4+ 12.Ka6 Db6#
Black mates: -+ (-#12) Depth: 31/43 00:00:06 150MN, tb=596106

, regards

[peter]

2kr4/2n5/5Qp1/2p5/2P1p3/P1B1P3/2K2P2/5q2 b - - 0 1

Analysis by SlowChess Blitz 2.9 avx2:

1...Dxc4 2.a4 De2+ 3.Kb3 c4+ 4.Ka3 Dc2 5.Dxd8+ Kxd8 6.Kb4 Kd7 7.Kxc4 Kc6 8.Kd4 Kd6 9.Kc4 Sd5 10.Kb5 Db3+ 11.Lb4+ Dxb4+ 12.Ka6 Db6#
Black mates: -+ (-#12) Depth: 25/37 00:00:04 96568kN, tb=214183
...
1...Dxc4 2.a4 De2+ 3.Kb3 c4+ 4.Ka3 Dc2 5.Dxd8+ Kxd8 6.Kb4 Kd7 7.Kxc4 Kc6 8.Kd4 Kd6 9.Kc4 Sd5 10.Kb5 Db3+ 11.Lb4+ Dxb4+ 12.Ka6 Db6#
Black mates: -+ (-#12) Depth: 31/43 00:00:06 150MN, tb=596106

Edit- time over, further single one trials I had with
SF11: 7" to correct DTM,
Houdini 4 with DTM given at UCI- option 12: <30",
Zappa Mex.2 with mate extensions on: 1' to -#12
The Huntsman (Jörg Oster) almost at once at -#15, takes about 2' for correct DTM .
Minic 3.30 with MateFinder option checked: about 2 minutes for #16, then gets stuck with fail high to resolve next iteration, broke off after 5'.

Here's SF dev., NNUE- usage switched off:

2kr4/2n5/5Qp1/2p5/2P1p3/P1B1P3/2K2P2/5q2 b - - 0 1

Analysis by Stockfish 110922:

Code: Select all

1...Dxc4 2.Dxd8+ Kxd8 3.Kb2 Ke7 4.Le5 De2+ 5.Kc3 Sd5+ 6.Kb3 c4+ 7.Ka4 Dxf2 
  Black is clearly winning: -+ (-9.49)  Depth: 10/13   00:00:00
...
  Black is clearly winning: -+ (-71.36)  Depth: 25/35   00:00:01  70393kN
1...Dxc4 2.Dxd8+ Kxd8 3.Kb2 De2+ 4.Kb3 Dxf2 5.La5 Dxe3+ 6.Kb2 Df2+ 7.Kc1 Df1+ 8.Kd2 Dd3+ 9.Ke1 Dxa3 10.Lb6 Db4+ 11.Ke2 Dxb6 12.Kf1 Db1+ 13.Kg2 Db2+ 14.Kg3 Dc3+ 15.Kf4 e3 16.Kf3 Da3 17.Ke2 Db2+ 18.Kf3 
  Black mates: -+ (-#34)  Depth: 26/37   00:00:01  77529kN
1...Dxc4 2.Dxd8+ Kxd8 3.Kb2 De2+ 4.Kb3 Sd5 5.Le5 Kd7 6.Ld4 Dd3+ 7.Ka2 Dc2+ 8.Ka1 cxd4 9.exd4 Dxf2 10.Kb1 Dxd4 11.Kc2 Dc3+ 12.Kd1 Dxa3 13.Ke2 Df3+ 14.Kd2 Df2+ 15.Kc1 Dc5+ 16.Kd2 e3+ 17.Kd3 
  Black mates: -+ (-#22)  Depth: 27/41   00:00:01  94404kN
1...Dxc4 2.Dxd8+ Kxd8 3.Kb2 De2+ 4.Kc1 Sd5 5.Ld2 Dxf2 6.La5+ Kd7 7.Ld2 Sxe3 8.Lxe3 Dxe3+ 9.Kb2 Dd3 10.a4 e3 11.a5 Dd2+ 12.Kb1 Dxa5 13.Kb2 Dd2+ 14.Kb3 Db4+ 15.Ka2 e2 16.Ka1 e1D+ 17.Ka2 Deb1# 
  Black mates: -+ (-#17)  Depth: 28/41   00:00:02  107MN
1...Dxc4 2.Dxd8+ Kxd8 3.Kb2 De2+ 4.Kc1 Sd5 5.La5+ Kd7 6.Ld2 Dxf2 7.Kd1 Sxe3+ 8.Lxe3 Dxe3 9.a4 Dd3+ 10.Kc1 e3 11.a5 Dd2+ 12.Kb1 Dxa5 13.Kb2 Dd2+ 14.Kb3 Db4+ 15.Ka2 e2 16.Ka1 e1D+ 17.Ka2 Deb1# 
  Black mates: -+ (-#17)  Depth: 29/41   00:00:02  109MN
1...Dxc4 2.Dxd8+ Kxd8 3.Kb2 De2+ 4.Kc1 Sd5 5.La5+ Kd7 6.Ld2 Dxf2 7.Kd1 Sxe3+ 8.Lxe3 Dxe3 9.a4 Dd3+ 10.Kc1 e3 11.a5 Dc3+ 12.Kb1 e2 13.Ka2 Dxa5+ 14.Kb3 e1D 15.Kc4 Dab4+ 16.Kd3 Ded2# 
  Black mates: -+ (-#16)  Depth: 30/41   00:00:02  113MN
1...Dxc4 2.Dxd8+ Kxd8 3.Kb2 Sd5 4.La5+ Kd7 5.Ld2 De2 6.Kc2 Dxf2 7.Kc1 Sxe3 8.Lxe3 Dxe3+ 9.Kb2 Dd2+ 10.Kb3 Dd3+ 11.Kb2 e3 12.a4 e2 13.Ka2 Dc2+ 14.Ka3 e1D 15.a5 Dxa5# 
  Black mates: -+ (-#15)  Depth: 31/41   00:00:02  119MN
...
  Black mates: -+ (-#14)  Depth: 45/28   00:00:04  284MN
1...Dxc4 2.Db6 De2+ 3.Kb3 c4+ 4.Kb4 Dc2 5.Kxc4 Dd3+ 6.Kb3 Db1+ 7.Kc4 Dxb6 8.Ld4 Db1 9.Kc3 Kd7 10.Kd2 Tb8 11.Lb6 Txb6 12.f3 Sd5 13.fxe4 Tb2# 
  Black mates: -+ (-#13)  Depth: 46/26   00:00:05  328MN
1...Dxc4 2.Dxg6 De2+ 3.Kb3 c4+ 4.Kb4 Dc2 5.Df5+ Kb7 6.Kc5 Sa6+ 7.Kb5 Db3+ 8.Lb4 Sc7+ 9.Kc5 c3 10.Dc8+ Kxc8 11.Kc6 Dd5+ 12.Kb6 Db5+ 13.Ka7 Da6# 
...
1...Dxc4 2.a4 De2+ 3.Kb3 c4+ 4.Kb4 Sd5+ 5.Kc5 Sxf6 6.Lxf6 c3 7.f3 exf3 8.Lxd8 Dxe3+ 9.Kb4 c2 10.Lf6 c1D 11.Ld4 Dxd4+ 12.Kb5 Dcb2+ 13.Kc6 Db7# 
  Black mates: -+ (-#13)  Depth: 59/26   00:00:10  716MN
1...Dxc4 2.a4 De2+ 3.Kb3 c4+ 4.Kb4 Dc2 5.Dc6 Db3+ 6.Kc5 Dxc3 7.Dxe4 Da5+ 8.Kxc4 Dxa4+ 9.Kc3 Sb5+ 10.Kb2 Td2+ 11.Dc2+ Txc2+ 12.Kb1 Sc3# 
  Black mates: -+ (-#12)  Depth: 60/26   00:00:13  907MN
...
1...Dxc4 2.a4 De2+ 3.Kb3 c4+ 4.Kb4 Dc2 5.Dc6 Db3+ 6.Kc5 Dxc3 7.Dxe4 Da5+ 8.Kxc4 Dxa4+ 9.Kc3 Sb5+ 10.Kb2 Td2+ 11.Dc2+ Txc2+ 12.Kb1 Sc3# 
  Black mates: -+ (-#12)  Depth: 86/24   00:00:41  2702MN

With still Syzygy- Probe Limit 0 but NNUE on, -#13 is in output in 8", -#12 in 1'10" at a second single one try, so not so bad yet neither as for my personal pov