WAC.002 by evaluation?

[metax]

A common chess endgame rule says "two connected passers on the sixth beat a rook". Is there any program that happens to solve WAC.002 by eval?

[D]8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - -

[kgburcham]

[D] 8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - -

Stockfish 1.7

22.00 0:01 -5.01 1...Rxb2 2.Rxb2 c3 3.Rb6+ Kg7 4.Rb7+ Kh6 5.Rb6+ Kh5 6.Rf6 c2 7.Rxf5+ Kh6 8.Rf6+ Kg7 9.Rd6 c1Q 10.Rd7+ Kf6 11.Rd6+ Kf7 12.Rxd3 Ke6 13.Ke2 Qb2+ 14.Kf3 Qxh2 (17.259.716) 11063
23.01 0:04 -7.55 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.e4 c1Q 10.exf5+ Kxf5 11.Rd5+ Ke6 12.Rxd3 Qf1+ 13.Ke4 Qh1+ 14.Rf3 Qxh2 (54.881.696) 12258
24.01 0:05 -7.87 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.e4 c1Q 10.exf5+ Kxf5 11.Rd5+ Ke6 12.Rxd3 Qf1+ 13.Ke4 Qh1+ 14.Rf3 Qxh2 (71.470.176) 12587
25.01 0:06 -8.16 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.e4 c1Q 10.exf5+ Kxf5 11.Rd5+ Ke6 12.Rxd3 Qf1+ 13.Ke4 Qh1+ 14.Rf3 Qxh2 (88.514.722) 12867
26.01 0:09 -8.60++ 1...Rxb2 2.Rd1 d2 3.Ke2 c3 4.Rg1 d1N+ 5.Kxd1 Rb1+ 6.Kc2 Rxg1 7.h3 Re1 8.Kxc3 Rxe3+ 9.Kb4 Ke6 10.Kxa4 Rxh3 (127.390.465) 13409
26.01 0:10 -8.60 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.e4 c1Q 10.exf5+ Kxf5 11.Rd5+ Ke6 12.Rxd3 Qf1+ 13.Ke4 Qh1+ 14.Rf3 Qxh2 (136.748.054) 13423
27.01 0:13 -9.21++ 1...Rxb2 2.Rd1 d2 3.Ke2 c3 4.Rg1 d1N+ 5.Kxd1 Rb1+ 6.Kc2 Rxg1 7.h3 Re1 8.Kxc3 Rxe3+ 9.Kb4 Ke6 10.Kxa4 Rxh3 (179.988.825) 13719
27.01 0:14 -9.21 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.e4 c1Q 10.exf5+ Kxf5 11.Rd5+ Ke6 12.Rxd3 Qf1+ 13.Ke4 Qh1+ 14.Rf3 Qxh2 (194.228.484) 13757
28.01 0:20 -10.06++ 1...Rxb2 2.Rd1 d2 3.Ke2 c3 4.Rg1 d1N+ 5.Kxd1 Rb1+ 6.Kc2 Rxg1 7.h3 Re1 8.Kxc3 Rxe3+ 9.Kb4 Ke6 10.Kc4 Rxa3 (282.963.010) 14115
28.01 0:26 -10.46 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.Rxd3 c1Q 10.Ke2 Qb2+ 11.Kf3 Qxh2 12.Rc3 Qh3+ 13.Kf2 Qh4+ 14.Ke2 Qh1 (387.250.910) 14365
29.01 0:41 -12.04++ 1...Rxb2 2.Rd1 d2 3.Ke2 c3 4.Rg1 d1N+ 5.Ke1 Nxe3 6.Rg8 Ng2+ 7.Kd1 Nxf4 8.Rf8+ Ke6 9.Rd8 Ke7 10.Rc8 Rd2+ 11.Kc1 Nd3+ 12.Kb1 Rb2+ 13.Ka1 c2 (605.375.512) 14528
29.01 0:53 -12.40 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Kf2 d2 9.Rxc2 d1Q 10.Rc8 Qb3 11.Rd8+ Ke7 12.Ra8 Qxa3 13.Ra7+ Ke6 14.Rxh7 Qb2+ (788.246.198) 14633
30.01 1:04 -13.33 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Kf2 d2 9.Rxc2 d1Q 10.Rc8 Qb3 11.Rd8+ Ke7 12.Ra8 Qxa3 13.Ra7+ Ke6 14.Ke2 Qa2+ (949.161.964) 14710
31.01 1:29 -13.61 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.Rxd3 c1Q 10.Ke2 Qb2+ 11.Kf3 Qxh2 12.Rc3 Qh1+ 13.Kf2 Qa1 14.Rd3 Qa2+ (1.326.025.290) 14850
32.01 1:44 -14.38++ 1...Rxb2 2.Rd1 d2 3.Ke2 c3 4.Rg1 d1N+ 5.Ke1 Nxe3 6.Rg8 Ng2+ 7.Kd1 Nxf4 8.Rf8+ Ke6 9.Rd8 Ke7 10.Rc8 Rd2+ 11.Kc1 Nd3+ 12.Kb1 Rb2+ 13.Ka1 c2 (1.550.681.044) 14811
32.01 2:03 -15.15++ 1...Rxb2 2.Rd1 d2 3.Ke2 c3 4.Rg1 d1N+ 5.Kxd1 Rb1+ 6.Kc2 Rxg1 7.h3 Re1 8.Kd3 c2 9.Kxc2 Rxe3 10.Kd2 Rxa3 11.h4 h5 12.Ke2 Ke6 13.Kd2 Rb3 14.Kc2 Rf3 (1.838.208.520) 14825
32.01 2:05 -15.15 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.Rc8 d2 10.Rc6+ Kf7 11.Rxc2 d1Q+ 12.Re2 Ke6 13.h4 Qf1+ 14.Rf2 Qd3 (1.858.181.273) 14809
33.01 2:14 -13.45-- 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.e4 fxe4+ 10.Kxe4 c1Q 11.f5+ Kf6 12.Rd6+ Kg5 13.Rxd3 Qf4+ 14.Kd5 (2.003.172.061) 14855
33.01 2:43 -16.84++ 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.e4 fxe4+ 10.Kxe4 c1Q 11.f5+ Kf6 12.Rd6+ Kg5 13.Rxd3 Qf4+ 14.Kd5 Qxh2 (2.416.769.062) 14778
33.01 3:53 -17.65 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.Rxd3 c1Q 10.Ke2 Qb2+ 11.Kd1 Qxh2 12.Rd2 Qh1+ 13.Ke2 Qa1 14.Rd3 Qb2+ (3.430.147.205) 14709
34.01 6:35 -20.92++ 1...Rxb2 2.Rd1 d2 3.Ke2 c3 4.Rf1 d1Q+ 5.Kxd1 Rb1+ 6.Kc2 Rxf1 7.Kxc3 Rh1 8.h4 Rxh4 9.Kb4 h5 10.Kxa4 Rh1 11.Kb3 h4 12.a4 h3 13.Kb2 Rh2+ 14.Ka3 Re2 (5.723.776.338) 14463

[Matthias Gemuh]

8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - -

Stockfish 1.7

22.00 0:01 -5.01 1...Rxb2 2.Rxb2 c3 3.Rb6+ Kg7 4.Rb7+ Kh6 5.Rb6+ Kh5 6.Rf6 c2 7.Rxf5+ Kh6 8.Rf6+ Kg7 9.Rd6 c1Q 10.Rd7+ Kf6 11.Rd6+ Kf7 12.Rxd3 Ke6 13.Ke2 Qb2+ 14.Kf3 Qxh2 (17.259.716) 11063
23.01 0:04 -7.55 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb8 c2 7.Rc8+ Kd6 8.Rd8+ Ke6 9.e4 c1Q 10.exf5+ Kxf5 11.Rd5+ Ke6 12.Rxd3 Qf1+ 13.Ke4 Qh1+ 14.Rf3 Qxh2 (54.881.696) 12258

That seems to be by search, not eval.

Matthias.

[metax]

By search (almost) every engine can find it... The question is if there is a program that has good knowledge about connected passed pawns and can find it by eval.

[zamar]

A common chess endgame rule says "two connected passers on the sixth beat a rook".

This is one of those rules which are expressed "in human terms", but which are strictly not true.

Some exceptions:

a) rook can immediately capture one pawn.
b) rook can fork pawn and king with check
c) defending king can get in front of the pawns (with the aid of discovered check for example)

So it's a search issue anyway.

[metax]

A common chess endgame rule says "two connected passers on the sixth beat a rook".

This is one of those rules which are expressed "in human terms", but which are strictly not true.

Some exceptions:

a) rook can immediately capture one pawn.
b) rook can fork pawn and king with check
c) defending king can get in front of the pawns (with the aid of discovered check for example)

So it's a search issue anyway.

So you think an engine that would implement this rule in its evaluation would give a gross misevaluation in many positions where connected passed pawns play an important role?

[zamar]

So you think an engine that would implement this rule in its evaluation would give a gross misevaluation in many positions where connected passed pawns play an important role?

I'd say that exact version of that rule is so complicated that implementing it, is not worth it.

[Uri Blass]

A common chess endgame rule says "two connected passers on the sixth beat a rook". Is there any program that happens to solve WAC.002 by eval?

[D]8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - -

The rule is simply wrong and the program that solve WAC.002 by evaluation will also play Rxb2 in the following position after search of 3 plies Rxb2 Rxb2 c3 because 2 connected passers on the 6th beat a rook.

[D]8/7p/5k2/5p2/p1p2P2/Pr1p1KP1/1P1R3P/8 b - - 0 1

Uri

[metax]

A common chess endgame rule says "two connected passers on the sixth beat a rook". Is there any program that happens to solve WAC.002 by eval?

[D]8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - -

The rule is simply wrong and the program that solve WAC.002 by evaluation will also play Rxb2 in the following position after search of 3 plies Rxb2 Rxb2 c3 because 2 connected passers on the 6th beat a rook.

[D]8/7p/5k2/5p2/p1p2P2/Pr1p1KP1/1P1R3P/8 b - - 0 1

Uri

No, because it will see by search that the two connected passers get lost.

[Uri Blass]

A common chess endgame rule says "two connected passers on the sixth beat a rook". Is there any program that happens to solve WAC.002 by eval?

[D]8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - -

The rule is simply wrong and the program that solve WAC.002 by evaluation will also play Rxb2 in the following position after search of 3 plies Rxb2 Rxb2 c3 because 2 connected passers on the 6th beat a rook.

[D]8/7p/5k2/5p2/p1p2P2/Pr1p1KP1/1P1R3P/8 b - - 0 1

Uri

No, because it will see by search that the two connected passers get lost.

It is not going to see it by search if the remaining depth is too small
and if you do not care about cases when the remaining depth is too small then I do not see why do you need to see it by evaluation.

Uri