Basic endgames

[Henk]

A more difficult one.
Whites king did not move.
Bugs, bugs, bugs.

[d] 1Q6/8/K7/8/8/8/3pk3/8 w -

Code: Select all

Depth  Value   Time           Nodes
   1     908            1             26    b8b2 
   2     908            1            104    b8b2  e2d1 
   3     908            2            408    b8b2  e2d1  b2a1 
   4     908            7           1104    b8b2  e2d1  b2a1  d1c2 
   5     908           20           5311    b8b2  e2d1  b2a1  d1c2  a1a2 
   6     908           51          15048    b8b2  e2d1  b2a1  d1c2  a1a2  c2c1 
   7     908          114          36762    b8b2  e2d1  b2a1  d1c2  a1a2  c2c1  a2a1 
   8     908          244          78885    b8b2  e2d1  b2a1  d1c2  a1a2  c2c1  a2a3  c1b1 
   9     908          594         203198    b8b2  e2d1  b2a1  d1c2  a1a2  c2c1  a2a3  c1b1  a3b3 
  10     908         1260         433940    b8b2  e2d1  b2a1  d1c2  a1a2  c2c1  a2a3  c1b1  a3b3  b1a1 
  11     908         2779         956879    b8b2  e2d1  b2a1  d1c2  a1a2  c2c1  a2a3  c1b1  a3b3  b1a1  b3c2 
  12     908         5709        1953516    b8b2  e2d1  b2a1  d1c2  a1a2  c2c1  a2a3  c1b1  a3b3  b1c1  b3c3  c1d1 
  13     908        12400        4209141    b8b2  e2d1  b2a1  d1c2  a1a2  c2c1  a2a3  c1b1  a3b3  b1c1  b3c3  c1d1  c3b2 
  14     908        25065        8512702    b8b2  e2d1  b2a1  d1c2  a1a2  c2c1  a2a3  c1b1  a3b3  b1c1  b3c3  c1d1  c3b2  d1e1 
  15     908        52350       17663146    b8b2  e2d1  b2a1  d1c2  a1a2  c2c1  a2a3  c1b1  a3b3  b1c1  b3c3  c1d1  c3b2  d1e1  b2c3 
  16     908       146226       42176824    b8b2  e2e1  b2c3  e1d1  c3a1  d1c2  a1a2  c2c1  a2a3  c1b1  a3b3  b1c1  b3e3  c1d1  e3g1  d1c2 
  17     908       255977       78640911    b8b2  e2e1  b2c3  e1e2  c3c2  e2e1  c2e4  e1d1  e4b1  d1e2  b1a2  e2d1  a2a1  d1c2  a1a4  c2b1  a4b3 
Analysis stopped

Added distance from king to opponent passed pawn. At least king moves to pawn.

Code: Select all

  16     905       258510       40048505    b8h2  e2e1  h2g3  e1f1  g3d3  f1e1  d3e3  e1d1  a6b5  d1c2  e3e4  c2c1  e4f4  c1d1  b5c4  d1c1 

[Henk]

This should be a draw:

[d] 1Q6/8/K7/8/8/8/2pk4/8 w - -

[Joost Buijs]

This should be a draw:

[d] 1Q6/8/K7/8/8/8/2pk4/8 w - -

Yes, this is a draw, but without table-bases it is not so easy for an engine to see. The queen can keep on giving checks from many different locations, so it will take quite some time before repetition detection kicks in.

[Henk]

This should be a draw:

[d] 1Q6/8/K7/8/8/8/2pk4/8 w - -

Yes, this is a draw, but without table-bases it is not so easy for an engine to see. The queen can keep on giving checks from many different locations, so it will take quite some time before repetition detection kicks in.

Stockfish:

Code: Select all

dep	score	nodes	time	(not shown:  tbhits	knps	seldep)
 35	  0.00 	181.3M	0:15.70	Qb2 Kd1 Qd4+ Kc1 Qc3 Kb1 Qb3+ Ka1 Qc4 Kb2 Qe2 Kb1 Qe4 Kc1 Qb7 Kd1 Qf3+ Kd2 Qf4+ Kd1 Qd6+ Ke2 Qh6 Kd1
 34	  0.00 	61.5M  	0:05.89	Qb2 Kd1 Qd4+ Kc1 Qc3 Kb1 Qb3+ Ka1 Qc4 Kb2 Qe2 Kb1 Qe4 Kb2 Qg2 Ka1 Qc6 Kb2
 33	  0.00 	21.8M  	0:02.52	Qb2 Kd1 Qd4+ Kc1 Qc3 Kb1 Qb3+ Ka1 Qc4 Kb2 Qe2 Kb1 Qe4 Kb2 Qg2 Ka1 Qg5 Kb2 Qg1 c1=Q Qxc1+ Kxc1 Ka5 Kd2 Kb6 Kc3 Kc5 Kb3 Kd4 Kb4 Kd3 Kb5 Kd2 Ka6 Kc1 Kb6
 32	  0.00 	14.7M  	0:01.88	Qb2 Kd1 Qd4+ Kc1 Qc3 Kb1 Qb3+ Ka1 Qc4 Kb2 Qe2 Kb1 Qe4 Kb2 Qg2 Ka1 Qg5 Kb2
 31	  0.00 	14.0M  	0:01.81	Qb2 Kd1 Qd4+ Kc1 Qc3 Kb1 Qb3+ Ka1 Qc4 Kb2 Qe2 Kb1 Qe4 Kb2 Qb7+ Ka1 Qc8 Kb2 Qb7+
 30	  0.00 	11.5M  	0:01.50	Qb2 Kd1 Qd4+ Kc1 Qc3 Kb1 Qb3+ Ka1 Qc4 Kb2 Qe2 Kb1 Qe4 Kb2 Qb4+
 29	+0.09 	6.17M  	0:00.85	Qb2 Kd1 Qd4+ Kc1 Qc3 Kd1 Qd3+ Kc1 Qd4 Kb1 Qb6+ Ka1 Qc6 Kb2 Qb5+ Ka2 Qa5+ Kb2 Qd2 Kb1 Ka5 c1=Q Qxc1+ Kxc1 Kb4 Kd2 Kc5 Kc3 Kb5 Kb3 Kb6 Ka3 Kc5 Kb2 Kd4 Kc2 Ke3 Kb3
 28	+0.09 	5.50M  	0:00.78	Qb2 Kd1 Qd4+ Kc1 Qc3 Kd1 Qd3+ Kc1 Qd4 Kb1 Qb6+ Ka1 Qc6 Kb2 Qb5+ Ka2 Qf1 Kb2 Qf2 Kc3 Qf4 Kb2 Qe5+ Kb1 Qf5 Ka1 Qg5 Kb1 Kb6 c1=Q Qxc1+ Kxc1 Kc5 Kb2 Kd6 Kc2 Ke6 Kb3 Kf5 Kb2 Kf6 Ka2
 27	+0.28 	2.39M  	0:00.36	Qb2 Kd1 Qd4+ Kc1 Qc3 Kd1 Qd3+ Kc1 Qd4 Kb1 Qb6+ Ka1 Qc6 Kb2 Qb5+ Ka3 Qa5+ Kb2 Qb4+ Ka2 Qe1 Kb2 Qf2 Kc1 Qg2 Kd1 Qg4+ Kd2 Qb4+ Kd1 Qd6+ Ke2 Qc6
 26	+0.28 	2.19M  	0:00.34	Qb2 Kd1 Qd4+ Kc1 Qc3 Kb1 Qb3+ Ka1 Qe3 Kb1 Qb6+ Ka1 Qc7 Kb1 Qh7 Kb2 Qb7+ Kc3 Qc8+ Kd2 Qd8+ Ke2 Qg5 Kd1 Qg4+ Kd2 Qb4+ Kd1 Qd6+ Ke2 Qc6 Kd2 Qd5+ Ke1
 25	+0.28 	2.08M  	0:00.33	Qb2 Kd1 Qd4+ Kc1 Qc3 Kb1 Qb4+ Ka2 Qe1 Kb2 Qe2 Kb3 Qf3+ Kb2 Qf6+ Kc1 Qg6 Kd2 Qd6+ Kc1 Qb8 Kd1 Qd8+ Ke2 Qg5 Kd1 Qd5+ Kc1 Qg2 Kb1 Qe4
 24	+6.47 	1.68M  	0:00.27	Qb2 Kd1 Qb3 Kd2 Qd5+ Kc1 Qg2 Kd1 Qg4+ Kd2 Qd4+ Kc1 Qc3 Kb1 Qb4+ Kc1 Qe1+ Kb2 Qf2 Kb3 Qf4 Kb2 Qb8+ Kc3
 23	+0.19 	1.50M  	0:00.24	Qb2 Kd1 Qb3 Kd2 Qd5+ Ke1 Qc4 Kd2 Qd4+ Kc1 Qc3 Kd1 Qd3+ Kc1 Qf3 Kd2 Qg2+ Kd1 Qg1+ Kd2 Qh2+ Kd1 Qd6+ Kc1 Ka7 Kb1 Qb6+ Kc1 Qb5 Kd2 Qb4+ Kd1 Qd4+ Kc1 Qc3 Kd1 Qd3+ Kc1
 22	+0.19 	1.47M  	0:00.24	Qb2 Kd1 Qb3 Kd2 Qd5+ Ke1 Qc4 Kd2 Qd4+ Kc1 Qc3 Kd1 Qd3+ Kc1 Qf3 Kd2 Qg2+ Kd1 Qg1+ Kd2 Qh2+ Kc1 Qh6+ Kd1 Qd6+ Kc1 Qc6
 21	+0.19 	1.35M  	0:00.22	Qb2 Kd1 Qb3 Kd2 Qd5+ Ke1 Qc4 Kd2 Qd4+ Kc1 Qc3 Kd1 Qf3+ Kc1 Qc6 Kb2 Qb5+ Ka3 Qd3+ Kb2 Qe2 Kb3 Qe3+ Kb2 Qe5+ Kc1 Qd4 Kb1 Qb6+ Ka1 Qh6 Kb2 Qg7+ Kb1 Qb7+ Ka1 Qc8 Kb2
 20	+6.47 	1.02M  	0:00.17	Qb2 Kd1 Qd4+ Kc1 Qd6 Kb2 Qe5+ Kc1 Qe1+ Kb2 Qe2 Kc3 Qe5+ Kd2 Qg5+ Kc3 Qc1 Kd3 Qb2 Kd2 Ka5
 19	+8.23 	698481	0:00.12	Qb2 Kd1 Qb3 Kd2 Qb4+ Kd1 Qd6+ Ke1 Qc6 Kd2 Qg2+ Kc3 Qg7+ Kd3 Qh6 Kc3 Qc1
 18	+0.12 	621653	0:00.11	Qb2 Kd1 Qb3 Kd2 Qb4+ Kd1 Qd6+ Ke1 Qc6 Kd2 Qg2+ Kd1 Qg1+ Kd2 Qd4+ Kc1 Ka5 Kb1 Qb6+ Ka1 Qc6
 17	+8.24 	289791	0:00.06	Qb2 Kd1 Qd4+ Kc1 Ka5 Kb1 Qb4+ Ka1 Qf4 Kb1 Qb8+ Ka1 Qh8+ Kb1 Qh7 Kc1 Qb7 Kd1 Qd7+ Kc1
 16	+8.24 	194739	0:00.04	Qb2 Kd1 Qd4+ Kc1 Ka5 Kb1 Qb4+ Ka1 Qf4 Kb2 Qb8+ Kc3 Qe5+ Kd2 Qb2 Kd3 Qb3+ Kd2 Qb4+ Kd3
 15	+6.94 	134118	0:00.03	Qb2 Kd1 Qd4+ Ke2 Qf4 Kd3 Qg3+ Kd2 Qg5+ Kd1 Qd5+ Kc1 Ka5 Kb2 Qb5+ Ka1
 14	+0.48 	111397	0:00.03	Qb2 Kd1 Qd4+ Ke1 Qe5+ Kd1 Qd6+ Kc1 Qb8 Kd2 Qf4+ Kd1 Qg4+ Kd2 Qg2+ Kc1 Ka5 Kb2
 13	+0.48 	73404  	0:00.02	Qb2 Kd1 Qd4+ Ke1 Qe5+ Kd1 Qd6+ Kc1 Ka5 Kb2 Qe5+ Kb1 Qb5+ Kc1 Ka4 Kd2
 12	+0.48 	41854  	0:00.01	Qb2 Kd1 Qd4+ Kc1 Ka5 Kb1 Qe4 Kb2 Qe2 Kb1 Qb5+ Kc1 Ka4 Kd2
 11	+0.48 	22621  	0:00.01	Qb2 Kd1 Qd4+ Kc1 Ka5 Kb1 Qb6+ Kc1 Ka4 Kd2 Qd4+ Kc1 Ka3
 10	+0.38 	20436  	0:00.01	Qb2 Kd1 Qd4+ Kc1 Qe5 Kb1 Qb8+ Kc1 Ka5 Kd1 Qd6+ Kc1 Ka4 Kb1 Qb8+ Kc1
  9	+0.38 	13696  	0:00.01	Qb2 Kd1 Qd4+ Kc1 Qe5 Kb1 Qb8+ Kc1 Ka5 Kd1
  8	+0.28 	7552    	0:00.01	Qb2 Kd1 Qd4+ Kc1 Qd6 Kb1 Qb8+ Kc1 Qb7 Kd2
  7	+0.28 	6421    	0:00.01	Qb2 Kd1 Qd4+ Kc1 Qd6 Kb1 Qb8+ Kc1 Qb7
  6	+0.28 	4637    	0:00.00	Qb2 Kd1 Qd4+ Kc1 Qd6 Kb1
  5	+0.28 	2678    	0:00.00	Qd8+ Kc1 Qd4 Kb1 Qc3 Kc1 Qe1+ Kb2
  4	+0.28 	1104    	0:00.00	Qb2 Kd1 Qd4+ Kc1 Qe3+ Kb1 Qe1+ Kb2
  3	+0.22 	774      	0:00.00	Qg3 c1=Q Qf2+ Kd1 Qf3+ Kd2
  2	+0.28 	384      	0:00.00	Qb2 Kd1
  1	+0.28 	135      	0:00.00	Qb2
  0	#
  

Maybe I should add this position to tablebase. But first have to implement tablebase. If I have time.
O wait position of white king also important.

[hgm]

There are two ways to handle this. You can program the knowledge into the evaluation, detecting the KQKP case with a 7th-rank a-, c-, f- or h-Pawn, and scoring it as drawish when the King supporting the Pawn is next to the promotion square, and the other far-enough away from it.

A more general way would be to recognize that progress against a 7th-rank Pawn with an insufficiently protected (empty) promotion square can only be made by approaching a second piece, and maintain a counter similar to the reversible move counter that resets only when you switch to moving another piece. And then score a position as very drawish when the value of this counter rises to, say, 5 or higher. This would even work with, f.e., an extra far-away Knight (KQNKP). Moving K or N would then allow black to convert to KQNKQ (which should be recognized as drawish), while sticking to Queen moves to check or attack an unprotected promotion square would drive up the counter to a drawish value. The only short-term escape would be to drive the black King to the promotion square (or capture the Pawn), and then reset the counter with a King or Knight move. You could even refine it by only resetting the counter for moves towards the promotion square.

[bob]

Pfft. It shouldn't get more complicated. Already took too much time.
Only counts distance from corner and distance between kings.
Maybe hash table needs to be rewritten for it does not take symmetry into account?

O wait I see I introduced a bug. To be provided.


[d] 4k3/8/8/R7/4K3/8/8/8 w - -

Code: Select all

Depth  Value   Time           Nodes
   1  261642   00:00:00            22    e4d3 
   2  261642   00:00:00            70    e4d3  e8d7 
   3  261642   00:00:00           600    e4d3  e8d7  d3c2 
   4  261642   00:00:10          1876    e4d3  e8d7  d3c2  d7c6 
   5  261642   00:00:22          7896    e4d3  e8d7  d3c2  d7c6  c2b1 
   6  261642   00:00:50         22369    e4d3  e8d7  d3c2  d7c6  c2b1  c6b6 
   7  261642   00:01:43         62033    e4d3  e8d7  d3c2  d7c6  c2b1  c6b6  b1a1 
   8  261642   00:05:10        138574    e4d3  e8d7  d3c2  d7c6  c2b1  c6b6  b1a1  b6a5 
   9  261642   00:10:34        323429    e4d3  e8d7  d3c2  d7c6  c2b1  c6b6  b1a1  b6a5 
  10  261642   00:16:04        632175    e4d3  e8d7  d3c2  d7c6  c2b1  c6b6  b1a1  b6a5 
  11  261642   00:15:26       1299875    e4d3  e8d7  d3c2  d7c6  c2b1  c6b6  b1a1  b6a5 
  12  261642   00:12:37       2128347    e4d3  e8d7  d3c2  d7c6  c2b1  c6b6  b1a1  b6a5 
  13  261642   00:27:42       3436668    e4d3  e8d7  d3c2  d7c6  c2b1  c6b6  b1a1  b6a5 
  14      M7   01:19:40       5891050    a5a7  e8d8  e4d5  d8c8  d5d6  c8b8  a7c7  b8a8  d6c5  a8b8  c5b6  b8a8  c7c8 
Analysis stopped

Do this in phases. (1) drive opposing king to edge of the board. You can use a PSQ table that has more negative numbers as the losing king gets closer to the edge. (2) get your king close to the opposing king, but honoring the PST so that it avoids the edge. Once you optimize that you ought to see a mate instantly.

[hgm]

Fairy-Max 5 uses a special PST for bare Kings, which increases the centralization bonus by a factor up to 11 compared to that of the opponent pieces. This was needed to make it win end-games where many weak pieces (all drawing to the center) have to cooperate in order to drive the bare King into a corner. (Which usually requires them to leave the center.) It turned out to be better to not apply the maximum factor immediately as the King gets bared, but switch it on graduately with the increase of the 50-move counter. That way the winning side will first focus on good positioning of his own pieces before starting the drive. Which is usually the way such end-games have to be played.

[JohnWoe]

Only "simple" endgame Sapeli usually have difficulties is KQkr.
It happens quite often.
I think having some special case code for these kind of endgames could be fruitful.

Here Sapeli 1.46 barely managed to find the win.

[pgn][Event "Computer Chess Game"] [Site "pc"] [Date "2019.09.21"] [Round "-"] [White "Sapeli 1.46"] [Black "Stockfish 8 64"] [Result "1-0"] [TimeControl "40/180"] [FEN "8/8/8/3r4/4k3/8/8/QK6 w - - 0 1"] [SetUp "1"] {-------------- . . . . . . . . . . . . . . . . . . . . . . . . . . . r . . . . . . . . k . . . . . . . . . . . . . . . . . . . Q K . . . . . . white to play --------------} 1. Qa8 {+6,01/10} Ke5 {-5,96/30 13} 2. Kc2 {+6,03/10 6} Ke4 {-5,96/31 0,1} 3. Kc3 {+6,01/9 6} Ke5 {-6,04/29 0,1} 4. Qg8 {+6,03/9 5} Rd6 {-50,73/29 5} 5. Qg5+ {+6,05/9 5} Ke6 {-50,73/31 0,1} 6. Kc4 {+6,06/9 5} Kd7 {-50,81/32 0,1} 7. Qe5 {+6,08/9 5} Re6 {-50,89/31 6} 8. Qf4 {+6,09/9 5} Ke7 {-50,97/33 6} 9. Kd5 {+6,10/9 5} Rg6 {-51,02/32 2,1} 10. Qc7+ {+6,12/9 4} Kf6 {-1000,28/31 24} 11. Qe5+ {+6,14/9 4} Kf7 {-1000,24/34 0,1} 12. Qf5+ {+6,10/9 4} Kg7 {-1000,24/35 0,5} 13. Ke5 {+6,12/9 4} Kh6 {-1000,23/35 1,1} 14. Qf8+ {+6,13/9 4} Kh5 {-1000,20/38 4} 15. Qc8 {+6,14/9 4} Kh4 {-1000,21/31 3} 16. Kf5 {+6,15/9 4} Rg2 {-50,97/22 2,5} 17. Qh8+ {+6,15/9 4} Kg3 {-5,80/1 0,1} 18. Qc3+ {+6,14/9 4} Kh2 {-1000,17/39 12} 19. Qe5+ {+6,14/9 4} Kg1 {-1000,16/41 1,1} 20. Qe1+ {+6,16/9 4} Kh2 {-1000,15/43 0,1} 21. Kf4 {+6,15/9 4} Rg7 {-1000,14/42 0,1} 22. Qe5 {+6,17/9 4} Rg3 {-1000,13/44 4} 23. Qc7 {+6,19/9 4} Kg2 {-1000,14/46 5} 24. Qc2+ {+6,19/9 4} Kh3 {-1000,13/48 0,1} 25. Qh7+ {+6,19/9 4} Kg2 {-5,92/1 0,1} 26. Qb7+ {+6,17/9 4} Kh2 {-1000,14/41 4} 27. Qb8 {+6,19/9 4} Kg2 {-1000,14/48 4} 28. Qb2+ {+6,19/10 4} Kh3 {-1000,13/51 0,1} 29. Qh8+ {+6,19/9 4} Kg2 {-5,92/1 0,1} 30. Qa8+ {+6,14/9 4} Kh2 {-1000,13/51 8} 31. Qa1 {+6,16/9 4} Rg2 {-1000,14/40 5} 32. Qh8+ {+6,18/9 4} Kg1 {-5,92/1 0,1} 33. Qb8 {+6,14/9 4} Kf1 {-1000,19/35 5} 34. Qb5+ {+6,16/9 4} Ke1 {-1000,16/39 7} 35. Qc4 {+6,16/9 4} Kf2 {-1000,15/42 0,1} 36. Qd5 {+6,19/9 4} Kf1 {-1000,17/41 8} 37. Qd1+ {+6,16/9 4} Kf2 {-5,84/1 0,1} 38. Qh1 {+6,15/9 4} Rg8 {-1000,13/54 24} 39. Qf3+ {+6,15/9 4} Ke1 {-1000,12/51 4} 40. Qe4+ {+12,08/9 4} Kf2 {-1000,11/64 15} 41. Qd4+ {+12,23/10 6} Ke1 {-1000,10/66 0,1} 42. Qa1+ {+12,20/9 6} Kd2 {-1000,09/71 0,6} 43. Qa2+ {+12,27/9 6} Kc3 {-1000,08/67 0,9} 44. Qxg8 {+12,32/9 6} Kb4 {-1000,07/75 0,1} 45. Qd5 {+12,37/8 5} Kc3 {-1000,06/81 2,6} 46. Ke3 {+12,43/8 5} Kc2 {-1000,05/95 10} 47. Qd3+ {+12,43/6 5} Kc1 {-1000,04/99 0,1} 48. Qd2+ {+104,85/5 0,1} Kb1 {-1000,03/127 0,1} 49. Kd4 {+104,85/4 0,1} Ka1 {-1000,02/1 0,1} 50. Kc3 {+104,85/3 0,1} Kb1 {-1000,01/127 0,1} 51. Qb2# {+104,85/2 0,1} {Xboard adjudication: Checkmate} 1-0 [/pgn]

[Guenther]

Micah, depth 18, 3548ms for mate score on an i7-8750H @ 2.2GHz

Code: Select all

2 cores: 2325 ms
3 cores: 2094 ms
4 cores: 1604 ms
5 cores: 1638 ms
6 cores: 955ms

Code: Select all

folkert@msi:~/Projects/git/Micah$ ./Micah 
position fen 4k3/8/8/R7/4K3/8/8/8 w - -
go depth 50
# took 0ms
# TB_RESULT_FAILED
info depth 1 score cp 0 nodes 27 time 0 nps 391253 pv a5a8
info depth 2 score cp 0 nodes 100 time 0 nps 839081 pv a5a8 e8d7 a8h8
info depth 3 score cp 0 nodes 322 time 0 nps 1395867 pv a5a8 e8d7 a8h8 d7c6
info depth 4 score cp 0 nodes 1289 time 0 nps 2101809 pv a5a8 e8d7 a8h8 d7c6 e4d3
info depth 5 score cp 0 nodes 3061 time 1 nps 2323651 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5
info depth 6 score cp 0 nodes 6395 time 2 nps 2273369 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2
info depth 7 score cp 0 nodes 12811 time 5 nps 2484447 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4
info depth 8 score cp 0 nodes 21415 time 8 nps 2543329 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1
info depth 9 score cp 0 nodes 34234 time 13 nps 2461084 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1 a4a3
info depth 10 score cp 0 nodes 54732 time 22 nps 2477201 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1 a4a3 b1a1
info depth 11 score cp 0 nodes 89872 time 36 nps 2441362 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1 a4a3 b1a1 a3b4
info depth 12 score cp 0 nodes 143662 time 60 nps 2381004 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1 a4a3 b1a1 a3b4 h8a8 b4c5
info depth 13 score cp 0 nodes 233902 time 98 nps 2378033 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1 a4a3 b1a1 a3b4 h8a8 b4c5 a8h8
info depth 14 score cp 0 nodes 417378 time 176 nps 2368492 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1 a4a3 b1a1 a3b4 h8a8 b4c5 a8h8 c5d6
info depth 15 score cp 0 nodes 714090 time 302 nps 2363819 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1 a4a3 b1a1 a3b4 h8a8 b4c5 a8h8 c5d6 h8a8 d6e7
info depth 16 score cp 0 nodes 1281045 time 549 nps 2332151 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1 a4a3 b1a1 a3b4 h8a8 b4c5 a8h8 c5d6 h8a8 d6e7
info depth 17 score cp 0 nodes 3117427 time 1326 nps 2349866 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1 a4a3 b1a1 a3b4 h8a8 b4c5 a8h8 c5d6 h8a8 d6e7 a8h8 e7d6 h8a8 d6e7 a8h8 e7d6 h8a8 d6e7 a8h8 e7d6
info depth 18 score cp 9978 nodes 8182666 time 3548 nps 2305941 pv a5a7 e8f8 e4d5 f8e8 d5e6 e8f8 a7e7 f8g8 e7f7 g8h8 e6f6 h8g8 f6g6 g8h8 f7e7 h8g8 e7e8

Giving a score of 0.00 until resolving the mate is strange.

[flok]

Micah, depth 18, 3548ms for mate score on an i7-8750H @ 2.2GHz

Code: Select all

2 cores: 2325 ms
3 cores: 2094 ms
4 cores: 1604 ms
5 cores: 1638 ms
6 cores: 955ms

Code: Select all

folkert@msi:~/Projects/git/Micah$ ./Micah 
position fen 4k3/8/8/R7/4K3/8/8/8 w - -
go depth 50
# took 0ms
# TB_RESULT_FAILED
info depth 1 score cp 0 nodes 27 time 0 nps 391253 pv a5a8
...
info depth 17 score cp 0 nodes 3117427 time 1326 nps 2349866 pv a5a8 e8d7 a8h8 d7c6 e4d3 c6b5 d3c2 b5a4 c2b1 a4a3 b1a1 a3b4 h8a8 b4c5 a8h8 c5d6 h8a8 d6e7 a8h8 e7d6 h8a8 d6e7 a8h8 e7d6 h8a8 d6e7 a8h8 e7d6
info depth 18 score cp 9978 nodes 8182666 time 3548 nps 2305941 pv a5a7 e8f8 e4d5 f8e8 d5e6 e8f8 a7e7 f8g8 e7f7 g8h8 e6f6 h8g8 f6g6 g8h8 f7e7 h8g8 e7e8

Giving a score of 0.00 until resolving the mate is strange.

Any suggestions for rules that could "hit" this?