En passant bonus

[Lyudmil Tsvetkov]

Just curious, how many authors still have not implemented a en passant bonus in their engines?

Of course, the bonus will be given to a pawn on the 5th rank, that has an enemy pawn on the 7th rank to the left or to the right of it.

Why is the bonus due?

3 main reasons:

1. The pawn on the 7th rank usually has as a natural option the right to make a double move, but with an enemy pawn on the 5th rank, this option becomes conditional, so this is certainly due some penalty.

2. The pawn on the 7th rank is, under all conditions, more or less backward.

3. The pawn on the 5th rank, if it is open, thretanes a dangerous lever on the 6th rank.

I think those conditions are solid enough not to miss the chance to assign the bonus.

Some examples:

[d]6k1/1p6/p7/P7/8/8/8/6K1 w - - 0 1
b7 is backward, so in this case this is redundant with backward pawns

[d]6k1/2pp4/1p6/1P6/8/8/8/6K1 w - - 0 1
c7 is semi-backward

[d]6k1/3p4/8/4P3/8/8/8/6K1 w - - 0 1
d7 is not strictly backward, but some degree of backwardness is still present; also, e5 threatens a dangerous lever on the 6th rank

[d]6k1/2pp4/8/1P6/8/8/8/6K1 w - - 0 1
c7 is somewhat backward, and b5 is a dangerous unopposed pawn that could become an open passer if c7 advances

[d]6k1/1pp5/8/2P5/8/8/8/6K1 w - - 0 1
b7 is not strictly backward, but some degree of backwardness is present; also, c5 threatens levering on the 6th rank

[d]6k1/2ppp3/8/4P3/8/8/8/6K1 w - - 0 1
d7 is not strictly backward, but some degree of backwardness is present; e6 threatens

I think the bonus could be small, some 5-7 cps, as this feature is quite frequent.

Of course, the bonus will be given to any pawn on the 5th rank able to capture en passant if an enemy pawn on the 7th rank advances doubly.

What is your assessment of this idea?

[Frank Quisinsky]

Hi Lyudmil,

Ep Bonus
Why not ... never heard from it.

Bonus for set mate with castling ... an other idea

You wonder, if you are searching in bigger Computer chess databases for such curios.

Have a look on end position ... stalemate!
Equinox will set mate ... Texel made stalemate.
Equinox produced some of such games ... lost 3 Points with stalemate problems in my 1.600 games round robin. Other tester will not see it ... because most are using resign = on. Game ended with mate, or draw ... not before with resign!

What I will say to you is ...
Each little changes can improved a lot.
So, what you wrote is interesting.

For you ... end of the game!
Sorry, have nothing to do with your message but after I am read that I must thinking on the Equinox stalemate problem.

[pgn][Event "FCP, 40/10, p=off, i7-4770k, 4.3GHz"]
[Site "Trier"]
[Date "2014.12.22"]
[Round "32.9"]
[White "Texel 1.04 x64"]
[Black "Equinox 3.30 x64"]
[Result "1/2-1/2"]
[ECO "E15"]
[PlyCount "184"]
[EventDate "2015.??.??"]
[EventType "tourn (rapid)"]
[EventRounds "50"]
[EventCountry "GER"]
[Source "Frank Quisinsky"]
[SourceDate "2015.02.09"]

1. d4 {[%eval 0,0] [%emt 0:00:00]} Nf6 {[%eval 0,0] [%emt 0:00:00]} 2. c4 {
[%eval 0,0] [%emt 0:00:00]} e6 {[%eval 0,0] [%emt 0:00:00]} 3. Nf3 {[%eval 0,0]
[%emt 0:00:00]} b6 {[%eval 0,0] [%emt 0:00:00]} 4. g3 {[%eval 0,0] [%emt 0:00:
00]} Bb4+ {[%eval 0,0] [%emt 0:00:00]} 5. Nbd2 {[%eval 0,0] [%emt 0:00:00]} Ba6
{[%eval 0,0] [%emt 0:00:00]} 6. Qc2 {[%eval 0,0] [%emt 0:00:00]} O-O {[%eval 0,
0] [%emt 0:00:00]} 7. a3 {[%eval 0,0] [%emt 0:00:00]} Bxd2+ {[%eval 0,0] [%emt
0:00:00]} 8. Bxd2 {[%eval 0,0] [%emt 0:00:00]} Bb7 {[%eval 0,0] [%emt 0:00:00]}
9. Bg2 {[%eval 0,0] [%emt 0:00:00]} d6 {[%eval 0,0] [%emt 0:00:00]} 10. b4 {
[%eval 0,0] [%emt 0:00:00]} h6 {[%eval 0,0] [%emt 0:00:00]} 11. O-O {[%eval 10,
18] [%emt 0:00:18]} Be4 {[%eval 13,20] [%emt 0:00:07]} 12. Qb2 {[%eval 10,18]
[%emt 0:00:17]} a6 {[%eval 14,22] [%emt 0:00:55] (Sc6)} 13. a4 {[%eval 23,19]
[%emt 0:00:17] (Tac1)} a5 {[%eval 10,21] [%emt 0:00:05] (Sc6)} 14. b5 {[%eval
23,21] [%emt 0:00:17]} Nbd7 {[%eval 2,22] [%emt 0:00:37]} 15. Bh3 {[%eval 27,
20] [%emt 0:00:17] (Ta3)} Bh7 {[%eval 0,22] [%emt 0:00:16] (Tc8)} 16. Ne1 {
[%eval 42,20] [%emt 0:00:17] (Tfd1)} e5 {[%eval 4,22] [%emt 0:00:13]} 17. Nf3 {
[%eval 32,19] [%emt 0:00:17] (Lg2)} exd4 {[%eval 19,22] [%emt 0:00:25] (De7)}
18. Nxd4 {[%eval 49,20] [%emt 0:00:19]} Ne4 {[%eval 16,23] [%emt 0:00:26]} 19.
Be3 {[%eval 37,20] [%emt 0:00:17]} Qe8 {[%eval 16,22] [%emt 0:00:10]} 20. Ra3 {
[%eval 39,20] [%emt 0:00:17] (Sc6)} Ne5 {[%eval 17,21] [%emt 0:00:17]} 21. Rc1
{[%eval 50,20] [%emt 0:00:17] (Da2)} f5 {[%eval 15,22] [%emt 0:00:24]} 22. Bg2
{[%eval 53,19] [%emt 0:00:18] (Da2)} Qf7 {[%eval 11,23] [%emt 0:00:19]} 23. Qa2
{[%eval 38,20] [%emt 0:00:39] (f3)} Rae8 {[%eval 7,21] [%emt 0:00:13]} 24. Nf3
{[%eval 34,21] [%emt 0:00:17] (f3)} Nd7 {[%eval 3,21] [%emt 0:00:20] (Sg4)} 25.
Ne1 {[%eval 44,20] [%emt 0:00:17]} Qe6 {[%eval 2,20] [%emt 0:00:05] (Kh8)} 26.
Nd3 {[%eval 72,21] [%emt 0:00:17] (Kh1)} g5 {[%eval 0,20] [%emt 0:00:06] (Df7)}
27. Qb2 {[%eval 64,17] [%emt 0:00:20]} Re7 {[%eval 0,20] [%emt 0:00:03]} 28.
Rb3 {[%eval 59,18] [%emt 0:00:21] (Tc2)} Bg6 {[%eval 0,22] [%emt 0:00:27]} 29.
f4 {[%eval 40,17] [%emt 0:00:17] (Ta3)} Ndf6 {[%eval -2,21] [%emt 0:00:21]
(Kh7)} 30. Bd4 {[%eval 43,19] [%emt 0:00:18]} Ng4 {[%eval -2,21] [%emt 0:00:22]
(Kh7)} 31. Qc2 {[%eval 43,18] [%emt 0:00:18] (e3)} Rfe8 {[%eval -2,21] [%emt 0:
00:43] (Kh7)} 32. Qd1 {[%eval 43,18] [%emt 0:00:18] (e3)} Bf7 {[%eval -10,20]
[%emt 0:00:18] (Kh7)} 33. e3 {[%eval 0,19] [%emt 0:00:18] (Lf3)} Nc5 {[%eval
-2,20] [%emt 0:00:47] (Dg6)} 34. Ra3 {[%eval 43,19] [%emt 0:00:19]} Ne4 {
[%eval 0,20] [%emt 0:00:08]} 35. Qc2 {[%eval 37,17] [%emt 0:00:40]} Kh7 {
[%eval -1,21] [%emt 0:00:22]} 36. Qa2 {[%eval 43,19] [%emt 0:00:16] (Lf3)} Qg6
{[%eval -1,21] [%emt 0:00:19] (Lh5)} 37. Bf3 {[%eval 0,17] [%emt 0:00:22]} h5 {
[%eval 0,20] [%emt 0:00:18]} 38. Qe2 {[%eval 0,17] [%emt 0:00:31]} h4 {[%eval
-19,19] [%emt 0:00:12] (Sgf6)} 39. Bxg4 {[%eval 3,18] [%emt 0:00:12]} fxg4 {
[%eval -39,18] [%emt 0:00:00]} 40. Qxg4 {[%eval -68,17] [%emt 0:00:15]} Be6 {
[%eval -29,21] [%emt 0:00:08]} 41. Qf3 {[%eval -41,19] [%emt 0:00:12] (De2)}
Bf5 {[%eval -75,21] [%emt 0:00:17]} 42. Qg2 {[%eval -63,18] [%emt 0:00:12] (g4)
} Qh6 {[%eval -138,21] [%emt 0:00:39] (Dh5)} 43. g4 {[%eval -132,18] [%emt 0:
00:12] (Tf1)} gxf4 {[%eval -225,19] [%emt 0:00:33]} 44. Nxf4 {[%eval -150,19]
[%emt 0:00:12] (h3)} Bxg4 {[%eval -211,17] [%emt 0:00:00]} 45. h3 {[%eval -212,
20] [%emt 0:00:21] (Sd5)} Bf5 {[%eval -357,21] [%emt 0:00:17]} 46. Kh2 {[%eval
-245,21] [%emt 0:00:19]} Rg8 {[%eval -357,19] [%emt 0:00:00]} 47. Qe2 {[%eval
-215,21] [%emt 0:00:13]} Ng3 {[%eval -282,23] [%emt 0:00:31] (Tg3)} 48. Qf2 {
[%eval -215,22] [%emt 0:00:12]} Rf7 {[%eval -279,25] [%emt 0:00:42] (Se4)} 49.
Rg1 {[%eval -116,21] [%emt 0:00:18]} Be4 {[%eval -283,24] [%emt 0:00:10] (Tg5)}
50. Raa1 {[%eval -82,21] [%emt 0:00:12] (Lc3)} Qe6 {[%eval -282,24] [%emt 0:00:
33] (Dg5)} 51. Rac1 {[%eval -82,22] [%emt 0:00:12]} Qf5 {[%eval -282,23] [%emt
0:00:05] (Tff8)} 52. Rcd1 {[%eval -82,23] [%emt 0:00:13] (Lc3)} Rg5 {[%eval
-314,20] [%emt 0:00:18] (Dg5)} 53. Ra1 {[%eval -112,22] [%emt 0:00:51] (Tc1)}
Kg8 {[%eval -320,22] [%emt 0:00:20] (Tf8)} 54. Qe1 {[%eval -82,20] [%emt 0:00:
11] (Lc3)} Rf8 {[%eval -326,19] [%emt 0:00:13] (Lc2)} 55. Ra2 {[%eval -122,19]
[%emt 0:00:14] (Td1)} Kf7 {[%eval -342,21] [%emt 0:00:31]} 56. Rd2 {[%eval
-144,20] [%emt 0:00:31] (Tf2)} Ke7 {[%eval -360,23] [%emt 0:00:27]} 57. Rf2 {
[%eval -180,20] [%emt 0:00:18]} Ke8 {[%eval -360,21] [%emt 0:00:00]} 58. Qa1 {
[%eval -186,20] [%emt 0:00:43] (Lb2)} Kd7 {[%eval -376,21] [%emt 0:00:10] (Df7)
} 59. Bg7 {[%eval -169,21] [%emt 0:00:09] (De1)} Rf7 {[%eval -376,23] [%emt 0:
00:09]} 60. Bd4 {[%eval -201,19] [%emt 0:00:09]} Kc8 {[%eval -376,23] [%emt 0:
00:08]} 61. Qd1 {[%eval -244,20] [%emt 0:00:16] (De1)} Rf8 {[%eval -376,22]
[%emt 0:00:24] (Kb7)} 62. Bc3 {[%eval -289,20] [%emt 0:00:20] (De1)} Kb7 {
[%eval -376,21] [%emt 0:00:25]} 63. Qd4 {[%eval -260,20] [%emt 0:00:26] (Dd2)}
Qg6 {[%eval -429,21] [%emt 0:00:15]} 64. Qd1 {[%eval -332,21] [%emt 0:00:08]}
Qg8 {[%eval -429,19] [%emt 0:00:00]} 65. Bd4 {[%eval -375,20] [%emt 0:00:10]
(Dc1)} Qxc4 {[%eval -465,21] [%emt 0:00:13] (Sh1)} 66. Qa1 {[%eval -302,19]
[%emt 0:00:12] (Tb2)} Qf7 {[%eval -462,22] [%emt 0:00:09]} 67. Qb2 {[%eval
-293,20] [%emt 0:00:16] (De1)} Qf5 {[%eval -449,21] [%emt 0:00:14] (Kb8)} 68.
Bg7 {[%eval -316,20] [%emt 0:00:12] (Dd2)} Rf7 {[%eval -423,21] [%emt 0:00:08]}
69. Bc3 {[%eval -364,21] [%emt 0:00:10]} Rg8 {[%eval -414,22] [%emt 0:00:14]
(Sh5)} 70. Qb3 {[%eval -272,18] [%emt 0:00:21] (Le1)} Kb8 {[%eval -425,21]
[%emt 0:00:10] (Tg5)} 71. Ra2 {[%eval -299,19] [%emt 0:00:26] (Le1)} d5 {
[%eval -445,20] [%emt 0:00:13] (Tff8)} 72. Rf2 {[%eval -267,18] [%emt 0:00:09]
(Db2)} Rff8 {[%eval -419,21] [%emt 0:00:21] (Dc8)} 73. Qd1 {[%eval -291,18]
[%emt 0:00:05] (Db2)} Rg5 {[%eval -419,19] [%emt 0:00:09]} 74. Qd2 {[%eval
-297,18] [%emt 0:00:04]} Kb7 {[%eval -388,21] [%emt 0:00:20] (Tfg8)} 75. Bd4 {
[%eval -340,17] [%emt 0:00:04] (Db2)} Rg6 {[%eval -371,20] [%emt 0:00:09] (Sh5)
} 76. Qe1 {[%eval -208,18] [%emt 0:00:05] (Db2)} Kb8 {[%eval -371,21] [%emt 0:
00:05]} 77. Qd2 {[%eval -208,20] [%emt 0:00:04] (Dc3)} Rf7 {[%eval -371,22]
[%emt 0:00:07] (Dg5)} 78. Qe1 {[%eval -208,20] [%emt 0:00:08] (Db2)} Kb7 {
[%eval -371,22] [%emt 0:00:07] (Tg8)} 79. Qc3 {[%eval -208,19] [%emt 0:00:03]}
Ka8 {[%eval -363,21] [%emt 0:00:07] (Kb8)} 80. Be5 {[%eval -208,19] [%emt 0:00:
03] (Dd2)} Ka7 {[%eval -363,21] [%emt 0:00:07] (Kb7)} 81. Bxc7 {[%eval 0,21]
[%emt 0:00:12] (Ld4)} d4 {[%eval -123,19] [%emt 0:00:25] (Dg5)} 82. exd4 {
[%eval -74,20] [%emt 0:00:12]} Bb7 {[%eval -125,20] [%emt 0:00:30] (Tg8)} 83.
d5 {[%eval -54,18] [%emt 0:00:16]} Bxd5 {[%eval -131,20] [%emt 0:00:04]} 84.
Rd1 {[%eval -54,17] [%emt 0:00:12] (Dd4)} Be4 {[%eval -190,21] [%emt 0:00:34]
(Se4)} 85. Rfd2 {[%eval -89,18] [%emt 0:00:22] (De5)} Kb7 {[%eval -266,20]
[%emt 0:00:08]} 86. Be5 {[%eval -144,19] [%emt 0:00:17]} Rg8 {[%eval -266,18]
[%emt 0:00:00]} 87. Qc4 {[%eval -159,19] [%emt 0:00:12]} Re8 {[%eval -323,22]
[%emt 0:00:31]} 88. Ng2 {[%eval -144,19] [%emt 0:00:12] (Ld6)} Rxe5 {[%eval
-344,22] [%emt 0:00:22] (Sf1+)} 89. Rf2 {[%eval -183,20] [%emt 0:00:14] (Sxh4)}
Qxf2 {[%eval -32753,26] [%emt 0:00:17] (Tg7)} 90. Rd7+ {[%eval 0,31] [%emt 0:
00:12] (Dxf7+)} Rxd7 {[%eval -32757,50] [%emt 0:00:12]} 91. Qc7+ {[%eval 0,35]
[%emt 0:00:18] (Dc6+)} Ka8 {[%eval -32755,37] [%emt 0:00:23] (Txc7)} 92. Qb8+ {
[%eval 0,33] [%emt 0:00:27] (Dc8+)} Kxb8 {[%eval 0,100] [%emt 0:00:00]} 1/2-1/2[/pgn]

[Pio]

Hi Lyudmil!

I think it would be more appropriate to assign a mobility penalty for the pawns that cannot do the otherwise safe two squares push.

What I really think might be a good feature to implement is a bonus for having more pawns that have the safe two pawn push option than the opponent since this can be of vital importance in the endgame where it can force zugzwangs.

[Lyudmil Tsvetkov]

Hi Lyudmil,

Ep Bonus
Why not ... never heard from it.

Bonus for set mate with castling ... an other idea

You wonder, if you are searching in bigger Computer chess databases for such curios.

Have a look on end position ... stalemate!
Equinox will set mate ... Texel made stalemate.
Equinox produced some of such games ... lost 3 Points with stalemate problems in my 1.600 games round robin. Other tester will not see it ... because most are using resign = on. Game ended with mate, or draw ... not before with resign!

What I will say to you is ...
Each little changes can improved a lot.
So, what you wrote is interesting.

For you ... end of the game!
Sorry, have nothing to do with your message but after I am read that I must thinking on the Equinox stalemate problem.

[pgn][Event "FCP, 40/10, p=off, i7-4770k, 4.3GHz"]
[Site "Trier"]
[Date "2014.12.22"]
[Round "32.9"]
[White "Texel 1.04 x64"]
[Black "Equinox 3.30 x64"]
[Result "1/2-1/2"]
[ECO "E15"]
[PlyCount "184"]
[EventDate "2015.??.??"]
[EventType "tourn (rapid)"]
[EventRounds "50"]
[EventCountry "GER"]
[Source "Frank Quisinsky"]
[SourceDate "2015.02.09"]

1. d4 {[%eval 0,0] [%emt 0:00:00]} Nf6 {[%eval 0,0] [%emt 0:00:00]} 2. c4 {
[%eval 0,0] [%emt 0:00:00]} e6 {[%eval 0,0] [%emt 0:00:00]} 3. Nf3 {[%eval 0,0]
[%emt 0:00:00]} b6 {[%eval 0,0] [%emt 0:00:00]} 4. g3 {[%eval 0,0] [%emt 0:00:
00]} Bb4+ {[%eval 0,0] [%emt 0:00:00]} 5. Nbd2 {[%eval 0,0] [%emt 0:00:00]} Ba6
{[%eval 0,0] [%emt 0:00:00]} 6. Qc2 {[%eval 0,0] [%emt 0:00:00]} O-O {[%eval 0,
0] [%emt 0:00:00]} 7. a3 {[%eval 0,0] [%emt 0:00:00]} Bxd2+ {[%eval 0,0] [%emt
0:00:00]} 8. Bxd2 {[%eval 0,0] [%emt 0:00:00]} Bb7 {[%eval 0,0] [%emt 0:00:00]}
9. Bg2 {[%eval 0,0] [%emt 0:00:00]} d6 {[%eval 0,0] [%emt 0:00:00]} 10. b4 {
[%eval 0,0] [%emt 0:00:00]} h6 {[%eval 0,0] [%emt 0:00:00]} 11. O-O {[%eval 10,
18] [%emt 0:00:18]} Be4 {[%eval 13,20] [%emt 0:00:07]} 12. Qb2 {[%eval 10,18]
[%emt 0:00:17]} a6 {[%eval 14,22] [%emt 0:00:55] (Sc6)} 13. a4 {[%eval 23,19]
[%emt 0:00:17] (Tac1)} a5 {[%eval 10,21] [%emt 0:00:05] (Sc6)} 14. b5 {[%eval
23,21] [%emt 0:00:17]} Nbd7 {[%eval 2,22] [%emt 0:00:37]} 15. Bh3 {[%eval 27,
20] [%emt 0:00:17] (Ta3)} Bh7 {[%eval 0,22] [%emt 0:00:16] (Tc8)} 16. Ne1 {
[%eval 42,20] [%emt 0:00:17] (Tfd1)} e5 {[%eval 4,22] [%emt 0:00:13]} 17. Nf3 {
[%eval 32,19] [%emt 0:00:17] (Lg2)} exd4 {[%eval 19,22] [%emt 0:00:25] (De7)}
18. Nxd4 {[%eval 49,20] [%emt 0:00:19]} Ne4 {[%eval 16,23] [%emt 0:00:26]} 19.
Be3 {[%eval 37,20] [%emt 0:00:17]} Qe8 {[%eval 16,22] [%emt 0:00:10]} 20. Ra3 {
[%eval 39,20] [%emt 0:00:17] (Sc6)} Ne5 {[%eval 17,21] [%emt 0:00:17]} 21. Rc1
{[%eval 50,20] [%emt 0:00:17] (Da2)} f5 {[%eval 15,22] [%emt 0:00:24]} 22. Bg2
{[%eval 53,19] [%emt 0:00:18] (Da2)} Qf7 {[%eval 11,23] [%emt 0:00:19]} 23. Qa2
{[%eval 38,20] [%emt 0:00:39] (f3)} Rae8 {[%eval 7,21] [%emt 0:00:13]} 24. Nf3
{[%eval 34,21] [%emt 0:00:17] (f3)} Nd7 {[%eval 3,21] [%emt 0:00:20] (Sg4)} 25.
Ne1 {[%eval 44,20] [%emt 0:00:17]} Qe6 {[%eval 2,20] [%emt 0:00:05] (Kh8)} 26.
Nd3 {[%eval 72,21] [%emt 0:00:17] (Kh1)} g5 {[%eval 0,20] [%emt 0:00:06] (Df7)}
27. Qb2 {[%eval 64,17] [%emt 0:00:20]} Re7 {[%eval 0,20] [%emt 0:00:03]} 28.
Rb3 {[%eval 59,18] [%emt 0:00:21] (Tc2)} Bg6 {[%eval 0,22] [%emt 0:00:27]} 29.
f4 {[%eval 40,17] [%emt 0:00:17] (Ta3)} Ndf6 {[%eval -2,21] [%emt 0:00:21]
(Kh7)} 30. Bd4 {[%eval 43,19] [%emt 0:00:18]} Ng4 {[%eval -2,21] [%emt 0:00:22]
(Kh7)} 31. Qc2 {[%eval 43,18] [%emt 0:00:18] (e3)} Rfe8 {[%eval -2,21] [%emt 0:
00:43] (Kh7)} 32. Qd1 {[%eval 43,18] [%emt 0:00:18] (e3)} Bf7 {[%eval -10,20]
[%emt 0:00:18] (Kh7)} 33. e3 {[%eval 0,19] [%emt 0:00:18] (Lf3)} Nc5 {[%eval
-2,20] [%emt 0:00:47] (Dg6)} 34. Ra3 {[%eval 43,19] [%emt 0:00:19]} Ne4 {
[%eval 0,20] [%emt 0:00:08]} 35. Qc2 {[%eval 37,17] [%emt 0:00:40]} Kh7 {
[%eval -1,21] [%emt 0:00:22]} 36. Qa2 {[%eval 43,19] [%emt 0:00:16] (Lf3)} Qg6
{[%eval -1,21] [%emt 0:00:19] (Lh5)} 37. Bf3 {[%eval 0,17] [%emt 0:00:22]} h5 {
[%eval 0,20] [%emt 0:00:18]} 38. Qe2 {[%eval 0,17] [%emt 0:00:31]} h4 {[%eval
-19,19] [%emt 0:00:12] (Sgf6)} 39. Bxg4 {[%eval 3,18] [%emt 0:00:12]} fxg4 {
[%eval -39,18] [%emt 0:00:00]} 40. Qxg4 {[%eval -68,17] [%emt 0:00:15]} Be6 {
[%eval -29,21] [%emt 0:00:08]} 41. Qf3 {[%eval -41,19] [%emt 0:00:12] (De2)}
Bf5 {[%eval -75,21] [%emt 0:00:17]} 42. Qg2 {[%eval -63,18] [%emt 0:00:12] (g4)
} Qh6 {[%eval -138,21] [%emt 0:00:39] (Dh5)} 43. g4 {[%eval -132,18] [%emt 0:
00:12] (Tf1)} gxf4 {[%eval -225,19] [%emt 0:00:33]} 44. Nxf4 {[%eval -150,19]
[%emt 0:00:12] (h3)} Bxg4 {[%eval -211,17] [%emt 0:00:00]} 45. h3 {[%eval -212,
20] [%emt 0:00:21] (Sd5)} Bf5 {[%eval -357,21] [%emt 0:00:17]} 46. Kh2 {[%eval
-245,21] [%emt 0:00:19]} Rg8 {[%eval -357,19] [%emt 0:00:00]} 47. Qe2 {[%eval
-215,21] [%emt 0:00:13]} Ng3 {[%eval -282,23] [%emt 0:00:31] (Tg3)} 48. Qf2 {
[%eval -215,22] [%emt 0:00:12]} Rf7 {[%eval -279,25] [%emt 0:00:42] (Se4)} 49.
Rg1 {[%eval -116,21] [%emt 0:00:18]} Be4 {[%eval -283,24] [%emt 0:00:10] (Tg5)}
50. Raa1 {[%eval -82,21] [%emt 0:00:12] (Lc3)} Qe6 {[%eval -282,24] [%emt 0:00:
33] (Dg5)} 51. Rac1 {[%eval -82,22] [%emt 0:00:12]} Qf5 {[%eval -282,23] [%emt
0:00:05] (Tff8)} 52. Rcd1 {[%eval -82,23] [%emt 0:00:13] (Lc3)} Rg5 {[%eval
-314,20] [%emt 0:00:18] (Dg5)} 53. Ra1 {[%eval -112,22] [%emt 0:00:51] (Tc1)}
Kg8 {[%eval -320,22] [%emt 0:00:20] (Tf8)} 54. Qe1 {[%eval -82,20] [%emt 0:00:
11] (Lc3)} Rf8 {[%eval -326,19] [%emt 0:00:13] (Lc2)} 55. Ra2 {[%eval -122,19]
[%emt 0:00:14] (Td1)} Kf7 {[%eval -342,21] [%emt 0:00:31]} 56. Rd2 {[%eval
-144,20] [%emt 0:00:31] (Tf2)} Ke7 {[%eval -360,23] [%emt 0:00:27]} 57. Rf2 {
[%eval -180,20] [%emt 0:00:18]} Ke8 {[%eval -360,21] [%emt 0:00:00]} 58. Qa1 {
[%eval -186,20] [%emt 0:00:43] (Lb2)} Kd7 {[%eval -376,21] [%emt 0:00:10] (Df7)
} 59. Bg7 {[%eval -169,21] [%emt 0:00:09] (De1)} Rf7 {[%eval -376,23] [%emt 0:
00:09]} 60. Bd4 {[%eval -201,19] [%emt 0:00:09]} Kc8 {[%eval -376,23] [%emt 0:
00:08]} 61. Qd1 {[%eval -244,20] [%emt 0:00:16] (De1)} Rf8 {[%eval -376,22]
[%emt 0:00:24] (Kb7)} 62. Bc3 {[%eval -289,20] [%emt 0:00:20] (De1)} Kb7 {
[%eval -376,21] [%emt 0:00:25]} 63. Qd4 {[%eval -260,20] [%emt 0:00:26] (Dd2)}
Qg6 {[%eval -429,21] [%emt 0:00:15]} 64. Qd1 {[%eval -332,21] [%emt 0:00:08]}
Qg8 {[%eval -429,19] [%emt 0:00:00]} 65. Bd4 {[%eval -375,20] [%emt 0:00:10]
(Dc1)} Qxc4 {[%eval -465,21] [%emt 0:00:13] (Sh1)} 66. Qa1 {[%eval -302,19]
[%emt 0:00:12] (Tb2)} Qf7 {[%eval -462,22] [%emt 0:00:09]} 67. Qb2 {[%eval
-293,20] [%emt 0:00:16] (De1)} Qf5 {[%eval -449,21] [%emt 0:00:14] (Kb8)} 68.
Bg7 {[%eval -316,20] [%emt 0:00:12] (Dd2)} Rf7 {[%eval -423,21] [%emt 0:00:08]}
69. Bc3 {[%eval -364,21] [%emt 0:00:10]} Rg8 {[%eval -414,22] [%emt 0:00:14]
(Sh5)} 70. Qb3 {[%eval -272,18] [%emt 0:00:21] (Le1)} Kb8 {[%eval -425,21]
[%emt 0:00:10] (Tg5)} 71. Ra2 {[%eval -299,19] [%emt 0:00:26] (Le1)} d5 {
[%eval -445,20] [%emt 0:00:13] (Tff8)} 72. Rf2 {[%eval -267,18] [%emt 0:00:09]
(Db2)} Rff8 {[%eval -419,21] [%emt 0:00:21] (Dc8)} 73. Qd1 {[%eval -291,18]
[%emt 0:00:05] (Db2)} Rg5 {[%eval -419,19] [%emt 0:00:09]} 74. Qd2 {[%eval
-297,18] [%emt 0:00:04]} Kb7 {[%eval -388,21] [%emt 0:00:20] (Tfg8)} 75. Bd4 {
[%eval -340,17] [%emt 0:00:04] (Db2)} Rg6 {[%eval -371,20] [%emt 0:00:09] (Sh5)
} 76. Qe1 {[%eval -208,18] [%emt 0:00:05] (Db2)} Kb8 {[%eval -371,21] [%emt 0:
00:05]} 77. Qd2 {[%eval -208,20] [%emt 0:00:04] (Dc3)} Rf7 {[%eval -371,22]
[%emt 0:00:07] (Dg5)} 78. Qe1 {[%eval -208,20] [%emt 0:00:08] (Db2)} Kb7 {
[%eval -371,22] [%emt 0:00:07] (Tg8)} 79. Qc3 {[%eval -208,19] [%emt 0:00:03]}
Ka8 {[%eval -363,21] [%emt 0:00:07] (Kb8)} 80. Be5 {[%eval -208,19] [%emt 0:00:
03] (Dd2)} Ka7 {[%eval -363,21] [%emt 0:00:07] (Kb7)} 81. Bxc7 {[%eval 0,21]
[%emt 0:00:12] (Ld4)} d4 {[%eval -123,19] [%emt 0:00:25] (Dg5)} 82. exd4 {
[%eval -74,20] [%emt 0:00:12]} Bb7 {[%eval -125,20] [%emt 0:00:30] (Tg8)} 83.
d5 {[%eval -54,18] [%emt 0:00:16]} Bxd5 {[%eval -131,20] [%emt 0:00:04]} 84.
Rd1 {[%eval -54,17] [%emt 0:00:12] (Dd4)} Be4 {[%eval -190,21] [%emt 0:00:34]
(Se4)} 85. Rfd2 {[%eval -89,18] [%emt 0:00:22] (De5)} Kb7 {[%eval -266,20]
[%emt 0:00:08]} 86. Be5 {[%eval -144,19] [%emt 0:00:17]} Rg8 {[%eval -266,18]
[%emt 0:00:00]} 87. Qc4 {[%eval -159,19] [%emt 0:00:12]} Re8 {[%eval -323,22]
[%emt 0:00:31]} 88. Ng2 {[%eval -144,19] [%emt 0:00:12] (Ld6)} Rxe5 {[%eval
-344,22] [%emt 0:00:22] (Sf1+)} 89. Rf2 {[%eval -183,20] [%emt 0:00:14] (Sxh4)}
Qxf2 {[%eval -32753,26] [%emt 0:00:17] (Tg7)} 90. Rd7+ {[%eval 0,31] [%emt 0:
00:12] (Dxf7+)} Rxd7 {[%eval -32757,50] [%emt 0:00:12]} 91. Qc7+ {[%eval 0,35]
[%emt 0:00:18] (Dc6+)} Ka8 {[%eval -32755,37] [%emt 0:00:23] (Txc7)} 92. Qb8+ {
[%eval 0,33] [%emt 0:00:27] (Dc8+)} Kxb8 {[%eval 0,100] [%emt 0:00:00]} 1/2-1/2[/pgn]

Hi Frank.

Yes, it is the end of the game for me, I am almost mated...

Unfortunately, you are the only one who is interested in my messages.

If Texel allowed stalemate, it must be similar to Reshevsky, who used to follow into frequent stalemate traps at least once every 11 years.

I think you will hear of even stranger concepts than an en passant bonus.

[Lyudmil Tsvetkov]

Hi Lyudmil!

I think it would be more appropriate to assign a mobility penalty for the pawns that cannot do the otherwise safe two squares push.

What I really think might be a good feature to implement is a bonus for having more pawns that have the safe two pawn push option than the opponent since this can be of vital importance in the endgame where it can force zugzwangs.

Is not this one and the same thing?

[lantonov]

This idea is already running on Fishtest by Vince Negri with attribution to Lyudmil Tsvetkov and passed STC (short-time control) convincingly.

Doesn't it go for Black too (black pawn on rank 4 and white en-passant pawn on rank 2) ?

Vince implemented a variant of this idea (weaker or stronger, I don't know) with black pawn on rank 5 and white pawn on rank 2.

[lucasart]

Isn't that redundant with backward pawns ?

[Lyudmil Tsvetkov]

This idea is already running on Fishtest by Vince Negri with attribution to Lyudmil Tsvetkov and passed STC (short-time control) convincingly.

Doesn't it go for Black too (black pawn on rank 4 and white en-passant pawn on rank 2) ?

Vince implemented a variant of this idea (weaker or stronger, I don't know) with black pawn on rank 5 and white pawn on rank 2.

Thanks to Mr. Negri.

I do not quite understand what rank 4 and rank 5 mean.

From white's point of view, the bonus should be due to any pawn on the 5th rank, with an enemy pawn on the 7th to the left or to the right on adjacent files.

This will hold true for both white and black.

The 7th rank is again seen from white's perspective, so actually the black pawn on the 7th rank from white's point of view is a pawn on the 2nd rank from black's point of view.

I posted quite some diagrams in my original message, you might want to look at them.

[Lyudmil Tsvetkov]

Isn't that redundant with backward pawns ?

Somewhat.

But in general engines define and consider just quite a few of all existing backward pawns, so the concept could possibly cover for some similar gaps.

Also, it could imply the creation of 6th-rank levers, in case the pawn on the 5th rank is free to move, or, the creation of open passers, in some particular cases.

I am also not certain about the size of the bonus in SF values.

[Frank Quisinsky]

Hi Luydmil,

yes I am reading your messages.
All the time interesting for me, I can learning a bit.
An highlight for a computer chess forum.
Be sure, that others read it.

In around 7 days Stockfish 6 BMI2 x64 is still running for my Rating List. Perhaps you have interest to give comments to the games. If so, I will upload each 160 new games the database!

Reshevsky?
Is a book available about it?
Must start my Research!
Knowledge gap by myself.

But later ...
Girlfriend to be advancing.
End of the nice computer chess time for today.

Best
Frank