Resign too early?

[marcelk]

During a rated standard game on FICS GNUchessSix with Black resigned in
the position below against Rookie with a +9 evaluation, but I wonder if it
isn't a fortress draw.

[d] 8/5p2/6k1/6P1/8/6Q1/p7/Kb6 w - -

White can win the pawn on a2, after that I don't see how White
can win the game after reaching

[d] 6k1/5p2/6bQ/6P1/8/8/K7/8 w - -

Rookie gives +10 here but the PV reveals endless shuffling. Can other
engines see a breakthrough from here or is it indeed a draw?

[Graham Banks]

During a rated standard game on FICS GNUchessSix with Black resigned in
the position below against Rookie with a +9 evaluation, but I wonder if it
isn't a fortress draw.

[d] 8/5p2/6k1/6P1/8/6Q1/p7/Kb6 w - -

White can win the pawn on a2, after that I don't see how White
can win the game after reaching

[d] 6k1/5p2/6bQ/6P1/8/8/K7/8 w - -

Rookie gives +10 here but the PV reveals endless shuffling. Can other
engines see a breakthrough from here or is it indeed a draw?

In the final diagram given, can't the White king just march to f6 and win?

[marcelk]

In the final diagram given, can't the White king just march to f6 and win?

Possibly, but I would expect the engine to find that rather easily.

[marcelk]

I just tested with a development version and a larger transposition
table and then sees a breakthrough to +15 at 21 ply. One of the changes
is to be more conservative with the null-move in the endgame, so that
might be it. Never mind..

[Michel]

In the final diagram GnuChess 5.07.171b sees a matescore very quicky.

[d] 6k1/5p2/6bQ/6P1/8/8/K7/8 w - -


The PV is weird since black sees it is lost and to delay the mate it sarcrifices its pieces. However I played it out and the winning plan is indeed to walk to f6.

Code: Select all

 24	+99.79	26.7M	0:17.05	Kb3 Bh5 Qxh5 Kf8 Qh6+ Ke7 Qf6+ Kd7 Qxf7+ Kc6 Qe7 Kb6 g6 Kc6 g7 Kb5 g8=Q Kc6 Qge6+ Kb5 Qg5# 
 23	+99.79	25.2M	0:16.18	Kb3 Bh5 Qxh5 Kf8 Qh6+ Ke7 Qf6+ Kd7 Qxf7+ Kc6 Qe7 Kb6 g6 Kc6 g7 Kb5 g8=Q Kc6 Qge6+ Kb5 Qg5# 
 22	+99.79	25.1M	0:16.13	Kb3 Bh5 Qxh5 Kf8 Qh6+ Ke7 Qf6+ Kd7 Qxf7+ Kc6 Qe7 Kb6 g6 Kc6 g7 Kb5 g8=Q Kc6 Qge6+ Kb5 Qg5# 
 21	+99.79	25.0M	0:16.10	Kb3 Bh5 Qxh5 Kf8 Qh6+ Ke7 Qf6+ Kd7 Qxf7+ Kc6 Qe7 Kb6 g6 Kc6 g7 Kb5 g8=Q Kc6 Qge6+ Kb5 Qg5# 
 20	+99.79	25.0M	0:16.06	Kb3 Bh5 Qxh5 Kf8 Qh6+ Ke7 Qf6+ Kd7 Qxf7+ Kc6 Qe7 Kb6 g6 Kc6 g7 Kb5 g8=Q Kc6 Qge6+ Kb5 Qg5# 
 19	+99.79	24.5M	0:15.81	Kb3 Bh5 Qxh5 Kf8 Qh6+ Ke7 Qf6+ Kd7 Qxf7+ Kc6 Qe7 Kb6 g6 Kc6 g7 Kb5 g8=Q Kc6 Qge6+ Kb5 Qg5# 
 18	+99.79	19.7M	0:12.78	Kb3 Bh5 Qxh5 Kf8 Qh6+ Ke7 Qf6+ Kd7 Qxf7+ Kd6 g6 Ke5 g7 Ke4 g8=Q Ke3 Qge8+ Kd2 Qd5+ Kc1 Qe1# 
 17	+99.79	19.2M	0:12.48	Kb3 Bh5 Qxh5 Kf8 Qh6+ Ke7 Qf6+ Kd7 Qxf7+ Kd6 g6 Ke5 g7 Ke4 g8=Q Ke3 Qge8+ Kd2 Qd5+ Kc1 Qe1# 
 16	+99.79	14.8M	0:09.88	Kb3 Bh5 Qxh5 Kf8 Qh6+ Ke7 Qf6+ Kd7 Qxf7+ Kd6 g6 Ke5 g7 Ke4 g8=Q Ke3 Qge8+ Kd2 Qd5+ Kc1 Qe1# 
 16	+99.77	11.2M	0:07.85	Kb2 Bh5 Qxh5 Kf8 Qh8+ Ke7 Qf6+ Ke8 Kb3 Kd7 Qxf7+ Kd6 g6 Ke5 g7 Ke4 g8=Q Ke3 Qge8+ Kd2 Qd5+ Kc1 Qe1# 
 15	+99.77	11.0M	0:07.71	Kb2 Bh5 Qxh5 Kf8 Qh8+ Ke7 Qf6+ Ke8 Kb3 Kd7 Qxf7+ Kd6 g6 Ke5 g7 Ke4 g8=Q Ke3 Qge8+ Kd2 Qd5+ Kc1 
 15	+99.69	2.8M	0:02.82	Kb3 
 15	+24.61	2.8M	0:02.82	Kb3 
 
  

[hgm]

Resigning is always too early. Even in KQBK there always is the chance for half a point.

[marcelk]

Resigning is always too early. Even in KQBK there always is the chance for half a point. :wink:

Absolutely. Rookie played hundreds of games on FICS while secretly
unable to mate with KRK due to the null move. Of course that is fixed now :)

[tano-urayoan]

This position [d] 6k1/5p2/6bQ/6P1/8/8/K7/8 w - -

is mate in 9 according to tablebases

[Vinvin]

It's an easy win with strong engines.
Black can't defend both pawns. After one pawn fall, the win is clear.

AMD 4200+ (2*2.2 Ghz)

Analysis by Houdini 1.5 x64:

...
1.De5 Rh5 2.Df4 Rg6 3.Rb2 Rh5 4.Dxf7+ Rxg5 5.Df3 Rg6 6.Df4 Ff5 7.Rxa2 Fe6+ 8.Rb2
+- (6.75) Profondeur: 11/23 00:00:00 161kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Dxf7 Rxg5 6.Dd5 Rg4 7.Rb2 Rf4
+- (6.84) Profondeur: 11/23 00:00:01 212kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Dxf7 Rxg5 6.Dd5 Rg4 7.Rb2 Rf4
+- (6.84) Profondeur: 12/23 00:00:01 231kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Rb2 Fe6 6.Dh4+ Re5 7.Rc3 Rf5 8.Rd4
+- (7.01) Profondeur: 13/28 00:00:01 512kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Rb2 Fe4 6.Rc3 Ff5 7.Dh4+ Rf3 8.Dd4 Fe6 9.Rd3
+- (7.13) Profondeur: 14/28 00:00:01 752kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Rb2 Fe4 6.Rc3 Fg6 7.Dh4+ Re5 8.Df2 Re4 9.Df6 Re3 10.Dd4+ Rf3 11.Rc4 Ff5 12.Df6
+- (7.27) Profondeur: 15/30 00:00:01 1129kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Rb2 Fg4 6.Dh6 Re4 7.Rc3 Ff5 8.Dh4+ Re3 9.Dd4+ Rf3 10.Df6 Rg4 11.Rd4 Rf4 12.Rd5 Rg4
+- (7.37) Profondeur: 16/33 00:00:01 2003kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Rb2 Fg4 6.Dh6 Re4 7.Rc3 Ff5 8.Dh4+ Re3 9.Dd4+ Rf3 10.Df6 Rg4 11.Rd4 Rf4 12.Rd5 Rg4
+- (7.37) Profondeur: 17/33 00:00:01 2681kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Rb2 Fg4 6.Dh4 Rf3 7.Rc3 Fe6 8.Rd4 Ff5 9.Re5 Fg6 10.Dd4 Rg3 11.Df4+ Rg2 12.Rf6 Rh3
+- (7.59) Profondeur: 18/34 00:00:02 4822kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Rb2 Fg6 6.Dh4+ Rf5 7.Rc3 Re6 8.Rd4 Rd6 9.Dg4 Re7 10.Dc8 Rd6 11.De8 Fh5 12.Dd8+ Re6 13.Dd5+ Re7 14.Db7+ Re6 15.Dd5+ Re7
+- (7.59) Profondeur: 19/41 00:00:03 8503kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Rb2 Fg6 6.Dh4+ Rf5 7.Rc3 Re6 8.Rd4 Rd6 9.Dg4 Re7 10.Dc8 Rd6 11.De8 Fh5 12.Dh8 Fg6 13.Dh2+ Re7 14.Dc7+ Re6 15.Dc8+ Rd6 16.De8
+- (7.59) Profondeur: 20/41 00:00:05 11805kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Rb2 Fg6 6.Dh4+ Rf5 7.Rc3 Re5 8.Rc4 Re6 9.Rd4 Rd6 10.Df2 Rd7 11.Re5 Rc6 12.Da7 Fh5 13.Dd4 Fg6 14.Df2 Rd7 15.Dc5 Re8 16.Dc8+ Re7
+- (7.62) Profondeur: 21/41 00:00:07 17914kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 a1T 4.Rxa1 Ff5 5.Rb2 Fg6 6.Dh4+ Rf5 7.Rc3 Re5 8.Rc4 Re6 9.Rd4 Rd6 10.Df2 Rd7 11.Re5 Rc6 12.Da7 Rb5 13.Dd4 Rc6 14.Df2 Rd7 15.Dc5 Re8 16.Dc8+ Re7
+- (7.63) Profondeur: 22/41 00:00:10 24771kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 Fg6 4.Dh4+ Rf5 5.Rxa2 Re5 6.Rb2 Re6 7.Rc3 Re5 8.Rc4 Re6 9.Rd4 Rd6 10.Df2 Re7 11.Re5 Rf8 12.Da7 Rg7 13.Dd7 Rf8 14.Rf6 Rg8
+- (7.63) Profondeur: 23/41 00:00:14 36887kN
1.Dh4
+- (7.94) Profondeur: 24/43 00:00:18 48346kN
1.Dh4
+- (8.57) Profondeur: 24/45 00:00:22 57339kN
1.Dh4
+- (10.34) Profondeur: 24/59 00:00:35 95366kN
1.Dh4
+- (15.53) Profondeur: 24/59 00:01:19 213741kN
1.Dh4 Rf5 2.Dh5 Rf4 3.Rb2 Fg6 4.Dh4+ Rf5 5.Rxa2 Re5 6.Rb2 Rf5 7.Rc3 Re5 8.Rc4 Fe4 9.Dh8+ Rf4 10.Df6+ Re3 11.Dxf7 Fd3+ 12.Rd5 Fb1 13.Df6 Fa2+ 14.Re5 Fg8 15.g6 Re2 16.g7 Fc4
+- (15.91) Profondeur: 24/65 00:02:02 324500kN

During a rated standard game on FICS GNUchessSix with Black resigned in
the position below against Rookie with a +9 evaluation, but I wonder if it
isn't a fortress draw.

[d] 8/5p2/6k1/6P1/8/6Q1/p7/Kb6 w - -

[marcelk]

This position [d] 6k1/5p2/6bQ/6P1/8/8/K7/8 w - -

is mate in 9 according to tablebases

Rookie sees the mate at 22 ply.