interesting endgame

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jdart
Posts: 4366
Joined: Fri Mar 10, 2006 5:23 am
Location: http://www.arasanchess.org

interesting endgame

Post by jdart »

This position occurred in an offline test game:

[D] 8/5k2/1p5P/p5P1/P1p1bP2/4P1K1/1P6/8 b - -

It looks like from a static eval viewpoint that White is ahead but in fact I believe Black is winning: the Black Bishop and King can hold off the White pawns, while Black can obtain a passer that White cannot stop. In the game Black played b5 and won.

Arasan 10.4 solves this but it takes a while and the score stays negative a long time:

no 1 0 -190 29 Bf5
no 2 50 -178 143 Bc2 Kg4 Bxa4
no 3 50 -150 593 Bc2 Kg4 Bd1+ Kf5 Bxa4
no 4 50 -103 1818 Bc2 Kg4 Kg6 Kf3 Bxa4
no 5 60 -103 8130 Bc2 Kf2 Kg6 Kf3 Bxa4
no 6 80 -125 23313 Bc2 Kf3 Kg6 e4 Bb3 Ke3 Bxa4
no 7 90 -121 45181 Bc2 Kf3 Kg6 e4 Bxa4 Ke3 Bd7
no 8 190 -140 151899 Ke6 Kg4 Bc2 Kf3 Kd5 Kg3 c3 e4+ Kxe4
no 9 330 -118 284942 Ke6 Kg4 Bc2 Kf3 Kd5 Ke2 Ke6 Kd2 Bxa4
no 10 890 -125 860018 Ke7 Kf2 Kd6 Ke2 Kc5 Kd2 Kb4 Kd1 Kb3 Kc1
Kxa4
no 11 2090 -93 2071109 Ke6 Kg4 Bg6 Kf3 Kd5 Ke2 Ke4 Kf2 Bh7 Kg3
Kxe3
no 12 3610 -78 3153073 Ke6 Kg4 Bg6 Kf3 Kd5 Ke2 Ke4 Kf2 Kd3 e4
Kxe4 Kg3
no 13 11530 -65 9742082 Kg6 Kf2 Kh5 Kf1 Kg4 Ke2 Kg3 Kd2 Kf3 Kc3
Kxe3 Kxc4 Kxf4
no 14 29670 -75 24067120 Ke6 Kg4 Bg6 Kf3 Kd5 Kg3 Bf5 Kg2 Ke4 Kf2
Kd3 e4 Kxe4 Kg3
no 15 72020 -43 70786713 c3 bxc3 b5 axb5 a4 f5 Bxf5 e4 Bc8 c4 a3
h7 Kg7 h8=Q+ Kxh8 c5
no 16 119590 +6 141287610 c3 bxc3
no 16 180090 +75 196958298 c3 bxc3 b5 axb5 a4 f5 Bxf5 e4 Bc8 b6 a3
e5 a2 e6+ Bxe6 h7 Kg7 h8=Q+ Kxh8 b7 a1=Q
b8=Q+ Kg7
yes 17 399640 +125 420415362 b5 axb5
yes 17 431050 +184 461537899 b5 axb5 a4 f5 Bxf5 b6 Bc8 e4 a3 bxa3 c3
e5 c2 e6+ Bxe6 h7 c1=Q h8=Q Qxa3+ Kf4
Qb4+ Ke3 Qxb6+ Ke4
yes 18 440660 +184 474109065 b5 axb5 a4 f5 Bxf5 b6 Bc8 e4 a3 bxa3 c3
e5 c2 e6+ Bxe6 h7 c1=Q h8=Q Qxa3+ Kf4
Qb4+ Ke3 Qxb6+ Ke4


Rybka 3 sees a Black advantage pretty quickly and finds b5 at depth 16 (68 seconds on my dual):

no 2 0 -24 60 Kg6
no 3 0 -34 92 Kg6
no 4 0 -33 142 Kg6
no 5 0 -35 222 Kg6 Kg4
no 6 20 -49 561 Kg6 Kg4 Bc2
no 7 80 -104 3448 Kg6 Kg4 Bf5+ Kf3
no 8 250 -124 11043 Kg6 Kg4 Bc2 Kf3
no 9 330 -141 14844 Kg6 Kg4 Bc2 Kf3 Bxa4 f5+ Kh7 e4 Bc2 f6
Kg6
no 9 580 -115 27256 Ke6 Kg4 Bg6 Kf3 Kd5 Kf2 Ke4
no 10 700 -115 33929 Ke6 Kg4 Bg6 Kf3 Kd5 Kg3 Ke6 Kf2 Kf5 Kf3
no 10 840 -95 42793 Kg6
no 10 910 -75 47803 Kg6
no 10 1020 -35 56157 Kg6
no 10 1770 +0 107323 Kg6 Kh4 Bf5 e4
no 11 1810 +0 109458 Kg6 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4
Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3
Be4 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4
Bf5
no 12 1880 +0 113065 Kg6 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4
Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3
Be4 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4
Bf5
no 13 3660 +0 218467 Kg6 Kf2 Kh5 Ke2 c3 bxc3 Kg4 Kf2 Bc2 Kg1
Be4 Kh2 Kh4 Kg1
no 14 3780 +0 228526 Kg6 Kf2 Kh5 Ke2 c3 bxc3 Kg4 Kf2 Bc2 Kg1
Be4 Kh2 Kh4 Kg1
no 14 10420 +20 731399 c3
no 14 12940 +40 934033 c3
no 14 15270 +80 1151851 c3
no 14 18340 +160 1452971 c3 bxc3 b5
no 14 26690 +319 2206665 c3 bxc3 b5
no 15 34890 +339 2988127 c3
no 15 41330 +359 3659637 c3
no 15 51590 +387 4633502 c3 bxc3 b5 axb5 a4 f5 Kg8 Kf4 a3 Kxe4 a2
c4 a1=Q Kd5 Qd1+ Ke5 Qd3
yes 16 68530 +387 6104641 b5 axb5 Kg8 f5 c3 bxc3
yes 17 84750 +407 7237671 b5
yes 17 99670 +427 8504776 b5
yes 17 121580 +467 10378259 b5
yes 17 208950 +512 16322459 b5

Shredder 10 does best on this: it plays b5 rapidly, although with a lower score.

(Note that I don't rule out that there are other winning moves).

Here is another interesting position derived from the first one:

[D] 8/5k2/7P/1P3bP1/p7/2P1P1K1/8/8 w - -

Rybka does less well on this: it thinks White is ok until it has a massive fail low at depth 12:


no 2 0 +165 380 c4
no 3 20 +185 601 Kf4
no 3 20 +205 608 Kf4
no 3 20 +245 625 Kf4
no 3 20 +156 668 Kf4
yes 3 20 +157 852 b6
yes 4 20 +177 1106 b6
yes 4 20 +197 1158 b6
yes 4 30 +218 1321 b6
yes 5 30 +146 2483 b6 a3 b7 a2 b8=Q
yes 6 90 +18 7250 b6 Bc8 e4
yes 7 330 +0 24318 b6 Bc8 e4 a3
yes 8 440 +0 32306 b6 Bc8 e4 a3 e5 a2 e6+ Bxe6 b7 a1=Q b8=Q
Qg1+ Kf3 Bg4+ Ke4 Qg2+ Kd4 Qd2+
yes 9 840 -16 61261 b6 Bc8 e4 a3 e5 a2 e6+ Bxe6 b7 a1=Q b8=Q
Qxc3+ Kf4 Qd2+ Kg3 Qxg5+
yes 10 1220 -16 89921 b6 Bc8 e4 a3 e5 a2 e6+ Bxe6 b7 a1=Q b8=Q
Qxc3+ Kf4 Qd2+ Kg3 Qxg5+
yes 11 1970 -16 140662 b6 Bc8 e4 a3 e5 a2 e6+ Bxe6 b7 a1=Q b8=Q
Qxc3+ Kf4 Qd2+ Kg3 Qxg5+ Kf2 Qf5+ Ke3
no 12 145630 -512 15021832 e4 a3
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bob
Posts: 20943
Joined: Mon Feb 27, 2006 7:30 pm
Location: Birmingham, AL

Re: interesting endgame

Post by bob »

jdart wrote:This position occurred in an offline test game:

[D] 8/5k2/1p5P/p5P1/P1p1bP2/4P1K1/1P6/8 b - -

It looks like from a static eval viewpoint that White is ahead but in fact I believe Black is winning: the Black Bishop and King can hold off the White pawns, while Black can obtain a passer that White cannot stop. In the game Black played b5 and won.

Arasan 10.4 solves this but it takes a while and the score stays negative a long time:

no 1 0 -190 29 Bf5
no 2 50 -178 143 Bc2 Kg4 Bxa4
no 3 50 -150 593 Bc2 Kg4 Bd1+ Kf5 Bxa4
no 4 50 -103 1818 Bc2 Kg4 Kg6 Kf3 Bxa4
no 5 60 -103 8130 Bc2 Kf2 Kg6 Kf3 Bxa4
no 6 80 -125 23313 Bc2 Kf3 Kg6 e4 Bb3 Ke3 Bxa4
no 7 90 -121 45181 Bc2 Kf3 Kg6 e4 Bxa4 Ke3 Bd7
no 8 190 -140 151899 Ke6 Kg4 Bc2 Kf3 Kd5 Kg3 c3 e4+ Kxe4
no 9 330 -118 284942 Ke6 Kg4 Bc2 Kf3 Kd5 Ke2 Ke6 Kd2 Bxa4
no 10 890 -125 860018 Ke7 Kf2 Kd6 Ke2 Kc5 Kd2 Kb4 Kd1 Kb3 Kc1
Kxa4
no 11 2090 -93 2071109 Ke6 Kg4 Bg6 Kf3 Kd5 Ke2 Ke4 Kf2 Bh7 Kg3
Kxe3
no 12 3610 -78 3153073 Ke6 Kg4 Bg6 Kf3 Kd5 Ke2 Ke4 Kf2 Kd3 e4
Kxe4 Kg3
no 13 11530 -65 9742082 Kg6 Kf2 Kh5 Kf1 Kg4 Ke2 Kg3 Kd2 Kf3 Kc3
Kxe3 Kxc4 Kxf4
no 14 29670 -75 24067120 Ke6 Kg4 Bg6 Kf3 Kd5 Kg3 Bf5 Kg2 Ke4 Kf2
Kd3 e4 Kxe4 Kg3
no 15 72020 -43 70786713 c3 bxc3 b5 axb5 a4 f5 Bxf5 e4 Bc8 c4 a3
h7 Kg7 h8=Q+ Kxh8 c5
no 16 119590 +6 141287610 c3 bxc3
no 16 180090 +75 196958298 c3 bxc3 b5 axb5 a4 f5 Bxf5 e4 Bc8 b6 a3
e5 a2 e6+ Bxe6 h7 Kg7 h8=Q+ Kxh8 b7 a1=Q
b8=Q+ Kg7
yes 17 399640 +125 420415362 b5 axb5
yes 17 431050 +184 461537899 b5 axb5 a4 f5 Bxf5 b6 Bc8 e4 a3 bxa3 c3
e5 c2 e6+ Bxe6 h7 c1=Q h8=Q Qxa3+ Kf4
Qb4+ Ke3 Qxb6+ Ke4
yes 18 440660 +184 474109065 b5 axb5 a4 f5 Bxf5 b6 Bc8 e4 a3 bxa3 c3
e5 c2 e6+ Bxe6 h7 c1=Q h8=Q Qxa3+ Kf4
Qb4+ Ke3 Qxb6+ Ke4


Rybka 3 sees a Black advantage pretty quickly and finds b5 at depth 16 (68 seconds on my dual):

no 2 0 -24 60 Kg6
no 3 0 -34 92 Kg6
no 4 0 -33 142 Kg6
no 5 0 -35 222 Kg6 Kg4
no 6 20 -49 561 Kg6 Kg4 Bc2
no 7 80 -104 3448 Kg6 Kg4 Bf5+ Kf3
no 8 250 -124 11043 Kg6 Kg4 Bc2 Kf3
no 9 330 -141 14844 Kg6 Kg4 Bc2 Kf3 Bxa4 f5+ Kh7 e4 Bc2 f6
Kg6
no 9 580 -115 27256 Ke6 Kg4 Bg6 Kf3 Kd5 Kf2 Ke4
no 10 700 -115 33929 Ke6 Kg4 Bg6 Kf3 Kd5 Kg3 Ke6 Kf2 Kf5 Kf3
no 10 840 -95 42793 Kg6
no 10 910 -75 47803 Kg6
no 10 1020 -35 56157 Kg6
no 10 1770 +0 107323 Kg6 Kh4 Bf5 e4
no 11 1810 +0 109458 Kg6 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4
Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3
Be4 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4
Bf5
no 12 1880 +0 113065 Kg6 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4
Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3
Be4 Kh4 Bf5 Kg3 Be4 Kh4 Bf5 Kg3 Be4 Kh4
Bf5
no 13 3660 +0 218467 Kg6 Kf2 Kh5 Ke2 c3 bxc3 Kg4 Kf2 Bc2 Kg1
Be4 Kh2 Kh4 Kg1
no 14 3780 +0 228526 Kg6 Kf2 Kh5 Ke2 c3 bxc3 Kg4 Kf2 Bc2 Kg1
Be4 Kh2 Kh4 Kg1
no 14 10420 +20 731399 c3
no 14 12940 +40 934033 c3
no 14 15270 +80 1151851 c3
no 14 18340 +160 1452971 c3 bxc3 b5
no 14 26690 +319 2206665 c3 bxc3 b5
no 15 34890 +339 2988127 c3
no 15 41330 +359 3659637 c3
no 15 51590 +387 4633502 c3 bxc3 b5 axb5 a4 f5 Kg8 Kf4 a3 Kxe4 a2
c4 a1=Q Kd5 Qd1+ Ke5 Qd3
yes 16 68530 +387 6104641 b5 axb5 Kg8 f5 c3 bxc3
yes 17 84750 +407 7237671 b5
yes 17 99670 +427 8504776 b5
yes 17 121580 +467 10378259 b5
yes 17 208950 +512 16322459 b5

Shredder 10 does best on this: it plays b5 rapidly, although with a lower score.

(Note that I don't rule out that there are other winning moves).
Crafty finds this very quickly, although it likes black after just a few plies, discovering the white pawns can't advance very quickly.

Code: Select all

               17     7.76  -1.36   1. ... b5 2. axb5 a4 3. b6 c3 4. bxc3
                                    a3 5. f5 a2 6. Kf4 Bb7 7. g6+ Kg8 8.
                                    h7+ <HT> &#40;s=2&#41;
               17->  10.43  -1.36   1. ... b5 2. axb5 a4 3. b6 c3 4. bxc3
                                    a3 5. f5 a2 6. Kf4 Bb7 7. g6+ Kg8 8.
                                    h7+ <HT> &#40;s=4&#41;
               18    13.39  -1.36   1. ... b5 2. axb5 a4 3. b6 c3 4. bxc3
                                    a3 5. f5 a2 6. g6+ Kg8 7. h7+ Kh8 8.
                                    Kf4 Bb7 <HT> &#40;s=3&#41;
               18->  17.32  -1.36   1. ... b5 2. axb5 a4 3. b6 c3 4. bxc3
                                    a3 5. f5 a2 6. g6+ Kg8 7. h7+ Kh8 8.
                                    Kf4 Bb7 <HT> &#40;s=2&#41;
               19    21.16     -1   1. ... b5!!    &#40;4.4Mnps&#41;             
               19    27.03     -3   1. ... b5!!    &#40;4.4Mnps&#41;             
               19    35.87  -2.39   1. ... b5 2. f5 bxa4 3. Kf4 c3 4. bxc3
                                    Kg8 5. Kxe4 a3 6. g6 a2 7. h7+ Kh8
                                    8. f6 a1=Q 9. f7 Qh1+ 10. Kd4 Kg7 11.
                                    c4 Qh4+ 12. e4 Qf6+ 13. e5 Qxg6
               19->  39.92  -2.39   1. ... b5 2. f5 bxa4 3. Kf4 c3 4. bxc3
                                    Kg8 5. Kxe4 a3 6. g6 a2 7. h7+ Kh8
                                    8. f6 a1=Q 9. f7 Qh1+ 10. Kd4 Kg7 11.
                                    c4 Qh4+ 12. e4 Qf6+ 13. e5 Qxg6
               20    49.28     -1   1. ... b5!!    &#40;4.5Mnps&#41;             
               20    57.39  -2.90   1. ... b5 2. f5 bxa4 3. Kf4 c3 4. bxc3
                                    a3 5. Kxe4 Kg8 6. g6 a2 <HT>
               20->   1&#58;01  -2.90   1. ... b5 2. f5 bxa4 3. Kf4 c3 4. bxc3
                                    a3 5. Kxe4 Kg8 6. g6 a2 <HT>
               21     1&#58;20  -3.07   1. ... b5 2. f5 bxa4 3. Kf4 c3 4. bxc3
                                    a3 5. Kxe4 Kg8 6. g6 a2 7. h7+ Kh8
                                    8. f6 a1=Q 9. f7 Qb1+ 10. Kd4 Qb6+
                                    11. Kd5 Qd8+ 12. Kc4 Kg7 13. e4 Kxg6


Here is another interesting position derived from the first one:

[D]

Rybka does less well on this: it thinks White is ok until it has a massive fail low at depth 12:


no 2 0 +165 380 c4
no 3 20 +185 601 Kf4
no 3 20 +205 608 Kf4
no 3 20 +245 625 Kf4
no 3 20 +156 668 Kf4
yes 3 20 +157 852 b6
yes 4 20 +177 1106 b6
yes 4 20 +197 1158 b6
yes 4 30 +218 1321 b6
yes 5 30 +146 2483 b6 a3 b7 a2 b8=Q
yes 6 90 +18 7250 b6 Bc8 e4
yes 7 330 +0 24318 b6 Bc8 e4 a3
yes 8 440 +0 32306 b6 Bc8 e4 a3 e5 a2 e6+ Bxe6 b7 a1=Q b8=Q
Qg1+ Kf3 Bg4+ Ke4 Qg2+ Kd4 Qd2+
yes 9 840 -16 61261 b6 Bc8 e4 a3 e5 a2 e6+ Bxe6 b7 a1=Q b8=Q
Qxc3+ Kf4 Qd2+ Kg3 Qxg5+
yes 10 1220 -16 89921 b6 Bc8 e4 a3 e5 a2 e6+ Bxe6 b7 a1=Q b8=Q
Qxc3+ Kf4 Qd2+ Kg3 Qxg5+
yes 11 1970 -16 140662 b6 Bc8 e4 a3 e5 a2 e6+ Bxe6 b7 a1=Q b8=Q
Qxc3+ Kf4 Qd2+ Kg3 Qxg5+ Kf2 Qf5+ Ke3
no 12 145630 -512 15021832 e4 a3
Crafty discovers e4 is no good at depth 13, and switches to b6 which is winning. Takes a second or two however...
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kgburcham
Posts: 2016
Joined: Sun Feb 17, 2008 4:19 pm

Old Deep Fritz 6

Post by kgburcham »

[D] 8/5k2/1p5P/p5P1/P1p1bP2/4P1K1/1P6/8 b - - 0 1

Deep Fritz:

1...b5!
= (0.12) Depth: 21/41 00:00:26 92694kN
1...b5!
= (-0.19) Depth: 22/44 00:00:57 239mN
1...b5 2.axb5 a4 3.f5 Bxf5 4.b6 Bc8 5.e4 a3 6.bxa3 c3 7.e5
-+ (-2.09) Depth: 22/44 00:01:26 355mN
1...b5!
-+ (-2.41) Depth: 23/44 00:02:16 558mN
1...b5!
-+ (-2.72) Depth: 24/46 00:03:44 923mN
1...b5 2.axb5 a4 3.f5 Bxf5 4.b6 Be4 5.Kf4 Bb7 6.Kf5 c3 7.bxc3
-+ (-5.03) Depth: 24/48 00:06:50 1758mN
1...b5!
-+ (-5.34) Depth: 25/47 00:10:31 2747mN
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beachknight
Posts: 3533
Joined: Tue Jan 09, 2007 8:33 pm
Location: Antalya, Turkey

Re: interesting endgame

Post by beachknight »

34: 8/5k2/1p5P/p5P1/P1p1bP2/4P1K1/ - Deep Fritz 11
8/5k2/1p5P/p5P1/P1p1bP2/4P1K1/1P6/8 b - - 0 1

Analysis by Crafty 22.01:

1...Kg6 2.Kh4 b5 3.axb5 c3 4.bxc3 a4 5.b6 a3 6.f5+ Kh7 7.f6 Kg6 8.Kg4 a2 9.Kf4 Bb7 10.h7 Kxh7 11.f7 Kg7
-+ (-2.94) Depth: 20 00:00:40 146mN, tb=4868
1...Kg6 2.Kh4 b5 3.axb5 c3 4.bxc3 a4 5.b6 a3 6.f5+ Kh7 7.f6 Kg6 8.Kg4 a2 9.h7 Kxh7 10.f7 Kg7 11.Kf4 Kxf7 12.Kxe4 a1Q
-+ (-3.29) Depth: 21 00:01:14 244mN, tb=6957
1...Kg6 2.Kh4 b5 3.axb5 c3 4.bxc3 a4 5.b6 a3 6.f5+ Kh7 7.f6 Kg6 8.Kg4 a2 9.h7 Kxh7 10.f7 Kg7 11.Kf4 Kxf7 12.Kxe4 a1Q
-+ (-3.69) Depth: 22 00:02:50 562mN, tb=20156
1...Kg6 2.Kh4 b5 3.axb5 c3 4.bxc3 a4 5.b6 a3 6.f5+ Kh7 7.f6 Kg6 8.Kg4 a2 9.h7 Kxh7 10.f7 Kg7 11.Kf4 Kxf7 12.Kxe4 a1Q
-+ (-3.29) Depth: 23 00:04:32 1003mN, tb=68708
1...Kg6 2.Kh4 b5 3.axb5 c3 4.bxc3 a4 5.b6 a3 6.f5+ Kh7 7.f6 Kg6 8.Kg4 a2 9.h7 Kxh7 10.f7 Kg7 11.Kf4 Bb7 12.g6 a1Q 13.c4
-+ (-4.04) Depth: 24 00:12:12 3032mN, tb=113618


(, chessengines20 28.11.2008 )
hi, merhaba, hallo HT
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beachknight
Posts: 3533
Joined: Tue Jan 09, 2007 8:33 pm
Location: Antalya, Turkey

Re: interesting endgame

Post by beachknight »

34: 8/5k2/1p5P/p5P1/P1p1bP2/4P1K1/ - Deep Fritz 11
8/5k2/1p5P/p5P1/P1p1bP2/4P1K1/1P6/8 b - - 0 1

Analysis by Toga CMLX 1.4 beta5d DC x64:

1...Kg8 2.f5 Bxf5 3.Kf4 Bc2 4.Ke5 c3 5.bxc3 Bxa4 6.Kd4 Bc6 7.e4 a4 8.Kc4 Bxe4 9.Kb4 Kh7 10.Kxa4 Bd3 11.c4 Bxc4 12.Kb4 Bd5 13.Kc3
-/+ (-1.32) Depth: 16/58 00:00:32 164mN
1...Kg6 2.f5+ Bxf5 3.Kf4 Bc2 4.Ke5 Kxg5 5.h7 Bxh7 6.Kd5 Bc2 7.Kc6 Kf5 8.Kxb6 Bxa4 9.Kc5 Ke4 10.Kxc4 Bd1 11.Kc3 Be2 12.Kd2 Bc4
-+ (-2.93) Depth: 16/63 00:02:12 396mN
1...Kg6 2.f5+ Bxf5 3.Kf4 Bc2 4.Ke5 Kxg5 5.Kd5 Kxh6 6.Kc6 Bxa4+ 7.Kxb6 Kg5 8.Kxa5 Bb3 9.Kb4 Kf5 10.Kc3 Ke4 11.Kd2 Kf3 12.e4 Kxe4 13.Kc3 Kd5
-+ (-3.23) Depth: 17/58 00:04:12 404mN
1...Kg6 2.f5+ Bxf5 3.Kf4 Bc2 4.Ke5 Kxg5 5.Kd6 Kxh6 6.Kc7 Bxa4 7.Kxb6 Kg5 8.Kxa5 Bb3 9.Kb4 Kf5 10.Kc3 Ke4 11.Kd2 Kf3 12.e4 Kxe4 13.Kc3 Kd5
-+ (-3.23) Depth: 17/61 00:04:14 404mN
1...Kg6 2.f5+ Bxf5 3.Kf4 Bc2 4.Ke5 Kxg5 5.Kd6 Kxh6 6.Kc7 Bxa4 7.Kxb6 Kg5 8.Kxa5 Bb3 9.Kb4 Kf5 10.Kc3 Ke4 11.Kb4 Kxe3 12.Kc3 Ke4 13.Kb4 Kd5
-+ (-3.23) Depth: 18/61 00:04:16 408mN
1...Kg6 2.f5+ Bxf5 3.Kf4 Bc2 4.Ke5 Kxg5 5.h7 Bxh7 6.Kd5 Bc2 7.Kxc4 Bxa4 8.Kd5 Kf5 9.e4+ Kf4 10.e5 Bb3+ 11.Kd6 Kf5 12.Kc6 Kxe5 13.Kxb6 a4 14.Kb5 Kd4 15.Kb4 Ke5
-+ (-3.42) Depth: 19/58 00:04:16 430mN
1...Kg6 2.f5+ Bxf5 3.Kf4 Bc2 4.Ke5 Kxg5 5.Kd5 Kxh6 6.Kc6 Bxa4+ 7.Kxb6 Bb3 8.Kxa5 Kg5 9.Kb4 Kf5 10.Kc3 Ke4 11.Kd2 Kf3 12.e4 Kxe4 13.Kc3 Ke3 14.Kb4 Kd4 15.Kb5 Bc2
-+ (-3.48) Depth: 20/63 00:04:16 457mN
1...Kg6 2.f5+ Bxf5 3.Kf4 Bc2 4.Ke5 Kxg5 5.Kd5 Kxh6 6.Kxc4 Bxa4 7.Kd5 Kg5 8.Kd6 Kf5 9.Kc7 Bc2 10.Kxb6 a4 11.Kb5 Ke4 12.Kc5 Kxe3 13.Kd5 Bd3 14.Kc5 Ke4 15.Kd6
-+ (-3.54) Depth: 21/63 00:04:16 506mN

(, chessengines20 28.11.2008 )
hi, merhaba, hallo HT
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pijl

Re: interesting endgame

Post by pijl »

jdart wrote:This position occurred in an offline test game:
/quote]

[D] 8/5k2/1p5P/p5P1/P1p1bP2/4P1K1/1P6/8 b - -
jdart wrote: It looks like from a static eval viewpoint that White is ahead but in fact I believe Black is winning: the Black Bishop and King can hold off the White pawns, while Black can obtain a passer that White cannot stop. In the game Black played b5 and won.[

The Baron immediately has a high score for black, intending to play c3 which (according to the Rybka analysis you posted) also a winning move. It switched to b5 after 45 seconds on depth 15 (on Core2 Duo, single CPU 1.67 Ghz):

Code: Select all

ply   score   time           nodes pv
 8&   2.182   0&#58;00.11        66259 c4c3 b2c3 b6b5 a4b5 a5a4 b5b6 a4a3 g3g4
 8.   2.182   0&#58;00.23       131296 c4c3 b2c3 b6b5 a4b5 a5a4 b5b6 a4a3 g3g4
 9&   2.810   0&#58;00.29       160717 c4c3 b2c3 b6b5 f4f5 b5a4 g3f4 e4c6 g5g6 f7f6 h6h7
 9.   2.810   0&#58;00.57       322149 c4c3 b2c3 b6b5 f4f5 b5a4 g3f4 e4c6 g5g6 f7f6 h6h7
10&   2.575   0&#58;00.68       387890 c4c3 b2c3 b6b5 a4b5 a5a4 f4f5 e4f5 g3f4 f7g6 b5b6
10.   2.575   0&#58;01.26       762416 c4c3 b2c3 b6b5 a4b5 a5a4 f4f5 e4f5 g3f4 f7g6 b5b6
11&   2.023   0&#58;01.49       912465 c4c3 b2c3 b6b5 f4f5 b5a4 g5g6 f7g8 g3f4 e4c6 f4g5 a4a3 f5f6
11.   2.023   0&#58;02.93      1906949 c4c3 b2c3 b6b5 f4f5 b5a4 g5g6 f7g8 g3f4 e4c6 f4g5 a4a3 f5f6
12&   2.418   0&#58;03.26      2138629 c4c3 b2c3 b6b5 a4b5 a5a4 b5b6 a4a3 f4f5 a3a2 g3f4 e4b7 g5g6 f7f6
12.   2.418   0&#58;05.33      3536966 c4c3 b2c3 b6b5 a4b5 a5a4 b5b6 a4a3 f4f5 a3a2 g3f4 e4b7 g5g6 f7f6
13&   1.547   0&#58;06.24      4192797 c4c3 b2c3 b6b5 a4b5 a5a4 b5b6 a4a3 f4f5 a3a2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7
13.   1.547   0&#58;13.55      9394396 c4c3 b2c3 b6b5 a4b5 a5a4 b5b6 a4a3 f4f5 a3a2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7
14&   1.532   0&#58;15.14     10615061 c4c3 b2c3 b6b5 a4b5 a5a4 b5b6 a4a3 f4f5 a3a2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7 f4e5 a2a1q
14.   1.532   0&#58;31.20     22251760 c4c3 b2c3 b6b5 a4b5 a5a4 b5b6 a4a3 f4f5 a3a2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7 f4e5 a2a1q
15&   1.532   0&#58;33.72     24166594 c4c3 b2c3 b6b5 a4b5 a5a4 b5b6 a4a3 f4f5 a3a2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7 f4e5 a2a1q
15&   1.757   0&#58;45.94     32372498 b6b5 a4b5 a5a4 b5b6 a4a3 b2a3 c4c3 f4f5 c3c2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7 f4e5 c2c1q
15.   1.757   0&#58;52.55     37066351 b6b5 a4b5 a5a4 b5b6 a4a3 b2a3 c4c3 f4f5 c3c2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7 f4e5 c2c1q
16&   1.782   0&#58;59.15     41642737 b6b5 a4b5 a5a4 b5b6 a4a3 b2a3 c4c3 f4f5 c3c2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7 f5f6 c2c1q a3a4
16.   1.782   1&#58;31.49     63788585 b6b5 a4b5 a5a4 b5b6 a4a3 b2a3 c4c3 f4f5 c3c2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7 f5f6 c2c1q a3a4
17&   2.244   1&#58;47.36     73871829 b6b5 a4b5 a5a4 b5b6 a4a3 b2a3 c4c3 f4f5 c3c2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7 f5f6 c2c1q f6f7 c1a3
17.   2.244   2&#58;41.52    109929031 b6b5 a4b5 a5a4 b5b6 a4a3 b2a3 c4c3 f4f5 c3c2 g5g6 f7g8 h6h7 g8h8 g3f4 e4b7 f5f6 c2c1q f6f7 c1a3
18&   1.909   3&#58;18.30    136664402 b6b5 a4b5 a5a4 b5b6 a4a3 b2a3 c4c3 f4f5 c3c2 g5g6 f7g8 g3f4 e4b7 h6h7 g8h8 f5f6
jdart wrote: Here is another interesting position derived from the first one:
[D] 8/5k2/7P/1P3bP1/p7/2P1P1K1/8/8 w - -

No problem for the Baron here:

Code: Select all

ply   score   time           nodes pv
 9.  -3.488   0&#58;00.12        82020 b5b6 f5c8 c3c4 a4a3 c4c5 a3a2 c5c6 a2a1q b6b7
10&  -3.734   0&#58;00.20       141513 b5b6 f5c8 e3e4 a4a3 e4e5 a3a2 e5e6 f7g6 e6e7 g6f7 h6h7
10.  -3.734   0&#58;00.29       175587 b5b6 f5c8 e3e4 a4a3 e4e5 a3a2 e5e6 f7g6 e6e7 g6f7 h6h7
11&  -2.575   0&#58;00.42       264248 b5b6 f5c8 e3e4 a4a3 e4e5 f7g6 e5e6 c8a6 g3f4 a3a2 e6e7
11.  -2.575   0&#58;00.46       280713 b5b6 f5c8 e3e4 a4a3 e4e5 f7g6 e5e6 c8a6 g3f4 a3a2 e6e7
12&  -2.930   0&#58;00.73       457191 b5b6 f5e4 g3f4 e4b7 f4f5 b7c8 f5e5 a4a3 e5d6 a3a2 d6c7 c8a6 g5g6 f7g6 b6b7
12.  -2.930   0&#58;00.81       503608 b5b6 f5e4 g3f4 e4b7 f4f5 b7c8 f5e5 a4a3 e5d6 a3a2 d6c7 c8a6 g5g6 f7g6 b6b7
13&  -2.626   0&#58;01.21       796724 b5b6 f5e4 g3f4 e4a8 e3e4 f7g6 e4e5 a4a3 e5e6 a3a2 e6e7 g6f7 h6h7
13.  -2.626   0&#58;01.41       918278 b5b6 f5e4 g3f4 e4a8 e3e4 f7g6 e4e5 a4a3 e5e6 a3a2 e6e7 g6f7 h6h7
14&  -2.655   0&#58;02.02      1355226 b5b6 f5e4 g3f4 e4c6 f4e5 a4a3 e5d6 c6f3 d6c7 a3a2 h6h7 f7g7 h7h8q g7h8 b6b7
14.  -2.655   0&#58;02.30      1551371 b5b6 f5e4 g3f4 e4c6 f4e5 a4a3 e5d6 c6f3 d6c7 a3a2 h6h7 f7g7 h7h8q g7h8 b6b7
15&  -3.265   0&#58;03.10      2134465 b5b6 f5e4 g3f4 e4c6 f4e5 a4a3 e5d6 c6e4 h6h7 f7g7 d6c7 a3a2 c3c4 a2a1q b6b7
15.  -3.265   0&#58;03.88      2701357 b5b6 f5e4 g3f4 e4c6 f4e5 a4a3 e5d6 c6e4 h6h7 f7g7 d6c7 a3a2 c3c4 a2a1q b6b7
16&  -4.467   0&#58;06.13      4152587 b5b6 f5e4 g3f4 e4b7 h6h7 f7g7 f4e5 a4a3 e5d6 a3a2 d6c7 b7e4 b6b7
16.  -4.467   0&#58;08.64      5813550 b5b6 f5e4 g3f4 e4b7 h6h7 f7g7 f4e5 a4a3 e5d6 a3a2 d6c7 b7e4 b6b7
17&  -4.587   0&#58;11.62      7838366 b5b6 f5e4 g3f4 e4b7 f4e5 a4a3 e5d6 a3a2 d6c7 b7e4 b6b7 e4b7 c7b7 a2a1q c3c4 f7g6 c4c5 g6g5
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jdart
Posts: 4366
Joined: Fri Mar 10, 2006 5:23 am
Location: http://www.arasanchess.org

Re: interesting endgame

Post by jdart »

Arasan has very simple endgame scoring (in fact the new version I am working on is even simpler than 10.4). But one thing it does have is a high bonus for connected passers, which is actually not helpful here, although it probably does help in other positions.

It looks like Baron has something quite different in endgame scoring.

--Jon
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jdart
Posts: 4366
Joined: Fri Mar 10, 2006 5:23 am
Location: http://www.arasanchess.org

Re: interesting endgame

Post by jdart »

Arasan at 3 hrs /move thinks b5 or c3 are far superior to other moves:

bm b5
result: b5 score: +6.56 ++ solved in 2073.58 sec. (7107.54M node
s)
b5 axb5 a4 f5 Bxf5 b6 Be4 Kf4 Bb7 Kf5 a3 bxa3 c3 g6+ Kg8 Kf6 c2 h7+ Kh8 Kf7 Bd5+
Kf6 c1=Q Ke5 Bb7 e4 Qxa3
result(2): c3 score: +7.04 ** not solved in 3600.05 secs. (
11833.48M nodes)
c3 bxc3 b5 axb5 a4 f5 Bxf5 b6 Be4 Kf4 Ba8 Kf5 a3 g6+ Kg8 Kf6 a2 h7+ Kh8 Kf7 Bd5+
Ke7 a1=Q Kd6 Bg2 b7 Bxb7 Kc7 Be4
result(3): Kg8 score: +2.06 ** not solved in 3600.15 secs. (
12390.05M nodes)
Kg8 f5 b5 axb5 a4 Kf4 a3 bxa3 c3 Kxe4 c2 g6 c1=Q h7+ Kh8 Kf4
bm b6
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pijl

Re: interesting endgame

Post by pijl »

jdart wrote: It looks like Baron has something quite different in endgame scoring.
The static evaluation score in the diagram position is about 1.4 for white. The Baron sees (statically) that the bishop and king are well positioned to obstruct the path of the connected passers, which reduces their bonus.
After c3 bxc3 b5 axb5 the static score of the Baron is already 1.8 for black, as it sees the promotion of the a-pawn. It this case it simply does not see that the bishop might become overcommitted in stopping the white pawns, and fortunately black will have a queen before it starts to become a problem. Needless to say that this backfires in some other positions.
Richard.
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smirobth
Posts: 2307
Joined: Wed Mar 08, 2006 8:41 pm
Location: Brownsville Texas USA

Re: interesting endgame

Post by smirobth »

bob wrote:
jdart wrote:
Here is another interesting position derived from the first one:

[D] 8/5k2/7P/1P3bP1/p7/2P1P1K1/8/8 w - -
Crafty discovers e4 is no good at depth 13, and switches to b6 which is winning. Takes a second or two however...
Your wording makes it sound like White is winning after b6, but unless I am mistaken it is Black who still wins after 1.b6 Be4
- Robin Smith
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