Does any engine see win here?

[Jouni]

[D]8/1k6/p7/1pb2K1R/8/P7/1P6/8 w - -

(Tiviakov,S.-Korsunsky,R.)

[syzygy]

Mate in 80:
[pgn][FEN "8/1k6/p7/1pb2K1R/8/P7/1P6/8 w - - 0 1"]
1.Ke4 Bb6 2.Kd5 Bd8 3.Rh7+ Kb6 4.Rg7 Bh4 5.a4 bxa4 6.Rg4 Bf2 7.Rxa4 Bg1 8.Ra1 Bf2 9.Rf1 Be3 10.Rf6+ Kb7 11.Rf3 Bg1 12.Kd6 Bh2+ 13.Ke6 Kc6 14.Rf1 Bg3 15.Kf5 Bd6 16.Rc1+ Kb6 17.Ke4 Bc5 18.Kd3 Kb5 19.Ra1 Kb6 20.Kc4 Be3 21.Re1 Bf2 22.Rf1 Be3 23.Rf3 Bg1 24.Kb4 Bd4 25.Rb3 Be5 26.Ka4+ Ka7 27.Ka5 Bf6 28.Kb4 Kb6 29.Ka4+ Ka7 30.Rb4 Be5 31.Kb3 Bd6 32.Re4 Kb7 33.Kc4 Bg3 34.Re2 Bb8 35.Rf2 Kb6 36.Rf6+ Kb7 37.Kd5 Bh2 38.Rg6 Bf4 39.Rg4 Bb8 40.Kc5 Ba7+ 41.Kd6 Bb8+ 42.Kd7 a5 43.Rc4 Kb6 44.Ke6 Kb5 45.Kd5 a4 46.Rc5+ Kb6 47.Kc4 Bf4 48.Rb5+ Ka6 49.Kc5 Be3+ 50.Kc6 Bc1 51.Rb8 Ka5 52.Kc5 Be3+ 53.Kc4 Bc1 54.Ra8+ Kb6 55.Rxa4 Be3 56.b4 Kc6 57.Ra1 Bf2 58.Rf1 Be3 59.Rf6+ Kd7 60.Kb5 Bd2 61.Rf3 Bg5 62.Ka6 Bc1 63.b5 Bb2 64.b6 Be5 65.Kb5 Bh2 66.Rd3+ Ke6 67.Kc6 Bg1 68.Rd6+ Ke7 69.b7 Ba7 70.Rd7+ Ke8 71.Rc7 Kf8 72.Rc8+ Ke7 73.Ra8 Bb8 74.Rxb8 Kf7 75.Ra8 Ke6 76.b8=Q Kf6 77.Ra5 Kg7 78.Qf4 Kh8 79.Rg5 Kh7 80.Qh2#[/pgn]

[Jouni]

Stunning! Is this with 6 piece DTM bases?

[syzygy]

Stunning! Is this with 6 piece DTM bases?

Yes. 6-piece WDL plus 5-piece DTM seems to be insufficient to solve this (it finds the TB win, but does not resolve it to a mate).

There may of course still be a shorter mate than 80 moves.

[zullil]

Stunning! Is this with 6 piece DTM bases?

Cfish with 6-man Syzygy tables sees a win in less than an second:

Code: Select all

info depth 25 seldepth 42 multipv 1 score cp 13258 nodes 35092312 nps 58003821 tbhits 330382 time 605 pv f5e4 c5f2 a3a4 b5b4 h5h7 b7b6 h7h6 b6b7 e4d5 f2g1 d5c4 b4b3 h6e6 g1f2 c4b3 f2d4 e6e7 b7b6 e7e4 d4f2 b3b4 f2c5 b4c4 c5f2 e4e6 b6a7 c4b4 f2h4 b4c5 a7b7 e6b6 b7a7 c5c6 h4f2

Providing Mate-in-80 will take longer!

[Nordlandia]

Famous 7-man study.

Nice test position for Ronald's DTM bases. White mates in 63 according Lomonosov. Just for comparison.

[d]b6k/7p/2p5/8/8/2N5/3B4/1K6 w - - 0 1

[d]k3N3/bp6/1p6/8/8/1N3K2/8/8 w - - 0 0 | Mate in 71

[d]r6N/1R6/B7/2k4p/8/2p5/8/1K6 w - - 0 0 | +7 according Sugar (5-men)

[d]8/8/3p4/4N3/8/B1k4p/4Pp1P/2K5 w - - 0 0 | Winning for black (cooked study)

[Nordlandia]

[d]k7/7b/2N3p1/7p/2B5/8/8/6K1 w - - 0 0 | Mate in 50

[d]k7/Bp6/1P6/Nn6/K7/8/8/8 w - - 0 1 | Mate in 36

[MikeGL]

Thanks a lot for this 7-men studies.
What chess magazine or publication was the source?

[Jouni]

I only have 5 piece syzygy set and I see after 100 plies SF fails to see win here. Why? This is a very rare REAL GAME position where you need 6 piece.

[D]8/8/pk6/3K4/R7/8/1P6/6b1 w - - 0 1

Analysis by Stockfish 9 64 BMI2:

8.Rb4+ Kc7 9.Re4 Kb6 10.Kc4 Kb7 11.Re6 Bf2 12.b3 Bh4 13.Re3 Kb6 14.Re2 Bg3 15.Re6+ Kb7 16.b4 Bh4 17.Re8 Bg5 18.Re5 Bf6 19.Re4 Bg5 20.Re2 Kb6 21.Ra2 Be3 22.Kc3 Kb7 23.Ra5 Kb6 24.Rf5 Kc6 25.Rf6+ Kb7 26.Re6 Bg5 27.Rd6 Be3 28.Rg6 Bf4 29.Kc4 Be3 30.Rg7+ Kc6 31.Rh7 Bg5 32.Rf7 Bd8 33.Rg7 Bh4 34.Rg6+ Kb7 35.Re6 Bg5 36.Kc5 Bd8 37.Re8 Bb6+ 38.Kc4 Kc7 39.Re6 Kb7 40.Re2 Bc7 41.Kc3 Bd6 42.Re8 Bc7 43.Re7 Kc6 44.Rh7 Be5+ 45.Kc4 Bg3 46.Rh5 Bf4 47.Rh8 Kb7 48.Rf8 Bb8 49.Re8 Ba7 50.Re7+ Kb6 51.Kb3 Bb8 52.Re6+ Kb7 53.Kc4 Ba7 54.Re2 Kc8 55.Kd5 Kb7 56.Re7+ Kb6 57.Kc4 Bb8 58.Re6+ Kb7 59.Kb3 Bf4 60.Rf6 Be3 61.Rf7+ Kc6 62.Kc3 Kb6 63.Kc4 Kc6 64.Rf6+ Kb7
+- (1.84) Depth: 101/112 00:05:47 5087mN, tb=15277736

[Nordlandia]

Thanks a lot for this 7-men studies.
What chess magazine or publication was the source?

Last two is from EG magazine.