man vs machine

[james uselton]

Carlsbad 1929---Capablanca makes a blunder on his 9th move and is a knight down with no compensation against Samisch. Does he resign---no! Should he have resigned? Capablanca fought tenaciously for another 53 moves---a knight down. Did Capablanca think it was hopeless.
A piece down against another GM with no compensation---did Capablanca think he was so far above Samisch that could actually pull it out?

[Mike S.]

Who'se assessment is that there was no compensation? In addition to a pawn for the knight, Seamisch had an isolated doubled pawn in c. That is of course not 100% compensation but some, if we can trust R232a:

[d]r3k2r/p1pq1ppp/1pbp1n2/4p3/Q1P1P3/P1PBBP2/6PP/R3K1NR w KQkq - 0 13

Analysis by Rybka 2.3.2a 32-bit :

13.Qc2 Qe6 14.Rb1 0-0 15.Nh3 h6 16.0-0 Rad8 17.Be2 Nh5 18.Rfd1 Qg6 19.Bf1
+- (1.61) Depth: 9 00:00:01 57kN
+- (1.53) Depth: 16 00:01:04 3162kN

[Terry McCracken]

Carlsbad 1929---Capablanca makes a blunder on his 9th move and is a knight down with no compensation against Samisch. Does he resign---no! Should he have resigned? Capablanca fought tenaciously for another 53 moves---a knight down. Did Capablanca think it was hopeless.
A piece down against another GM with no compensation---did Capablanca think he was so far above Samisch that could actually pull it out?

Yes, he should have resigned. I'm not going to argue about his ego.

[Uri Blass]

Carlsbad 1929---Capablanca makes a blunder on his 9th move and is a knight down with no compensation against Samisch. Does he resign---no! Should he have resigned? Capablanca fought tenaciously for another 53 moves---a knight down. Did Capablanca think it was hopeless.
A piece down against another GM with no compensation---did Capablanca think he was so far above Samisch that could actually pull it out?

Yes, he should have resigned. I'm not going to argue about his ego.

Unlike you I am not criticizing people for not resigning(even if they are full knight down).

People may decide not to resign even if they believe they have 1% chance to save the game and it is their right.

The fact that I expect 2300 player to win even against perfect play does not mean that the opponent has to resign.

I believe that 2300 player has a probability of more than 80% to win a game against every human or computer if the opponent starts without the knight b1.

It does not mean that 2300 or even a strong GM has probability of more than 99% to win in these condition against humans at similiar strength.

Uri

[jwes]

Carlsbad 1929---Capablanca makes a blunder on his 9th move and is a knight down with no compensation against Samisch. Does he resign---no! Should he have resigned? Capablanca fought tenaciously for another 53 moves---a knight down. Did Capablanca think it was hopeless.
A piece down against another GM with no compensation---did Capablanca think he was so far above Samisch that could actually pull it out?

Consider the cost versus the gain. The only cost is a few hours of playing chess (which he had been planning on doing anyway) while the gain would have turned out to be going from tied for 2nd to tied for 1st or 1st. Even if his odds were 1000 to 1 of saving a 1/2 point, it may have been worthwhile.

[lkaufman]

I think Rybka could be designed to play much stronger than it did with Knight odds. The problem is that it sees itself totally lost and doesn't see a way out. If the algo would try and complicate the position even if it is worse then the outcome might be different. For example it should be "taught" to stay in positions with as many pieces on the board as possible and to avoid any static non dynamic positions. The standard algo for normal chess simply is not tuned for that type of play. Still ... a knight handicap is a pretty big handicap and any reasonable chess player with some ability will simply try to exchange pieces and go into a dry technical ending a piece up.

Rybka 3 was indeed taught to avoid exchanges when behind, but forcing dynamic positions is easier said that done, especially when you must give priority to avoiding exchanges.

[fern]

No estoy tan seguro, Miguel que sea indubitable ganar "jugando con cuidado" si se tiene una pieza extra, salvo si dicha pieza es el rey enemigo. Contra un programa realmente fuerte, me refiero.
Es increíble lo mucho que decae nuestro juego si sentimos confianza.

Fernando

[lkaufman]

Someone should run a tournament testing weak engines against strong engines with piece odds so we can estimate how many elo a piece is worth.

I ran plenty of such matches about two years ago. The rating difference depends strongly on the time limiit; the slower the game, the greater the rating difference. Computers can give other computers knight odds successfully which are rated much higher than the typical human who needs knight odds. I recall that Rybka 3 on a quad was able to give knight odds in five minute chess with close to even results to Crafty (20.14 version I think) and to an older Fritz (5.32 I think).

[lkaufman]

Ok---you have the strongest chess program, and a state of the art computer. How much handicap would the leading Grandmasters need---to have a chance of winning?

I hosted something like eight or nine handicap matches between various Rybka versions (on a quad or octal) and Grandmasters at tournament or near-tournament time controls. We beat Ehlvest 5.5-2.5 giving each of the eight white pawns in turn, we beat him 4.5-1.5 giving him all White pieces + double time odds + 3 move limitation on Rybka book + no EGTB, we beat Benjamin 4.5-3.5 giving the eight pawns in turn with alternating colors, we beat Benjamin 6-2 giving draw and White odds in each game, we split 4-4 with Dzindzichashvili giving each of the eight pawns plus the White pieces, we beat Perelshteyn 1.5-0.5 giving 10 to 1 time ratio handicap plus White pieces. Against IM Eugene Meyer we won 3.5-0.5 giving pawn (f7) and two move handicap (!), against FM John Meyer we won 3-1 giving pawn (f7) and three moves handicap, but we lost to him 0-4 giving knight odds. Finally came the big match with (then) 2705 FIDE rated GM Vadim Milov. The terms were that in two games he got only the advantage of the White pieces, in two games he got the traditional pawn and move (f7), and in the other four he got the Exchange (remove a1 and b8). He lost 0.5-1.5 in the White games, he won by the same margin at pawn and move, and he scored one win and three draws at Exchange odds to win by the narrowest possible margin.
Conclusion: In a match today at a FIDE-ratable time control between a 2700 level GM (about the strongest we can expect to get to play such a match for a modest fee) and Rybka 3 or any comparable strength program, I would bet on the program at pawn handicap or even pawn and move except for the traditional f7 (or perhaps g7) handicap, which is more like 1.5 pawns and is too easily analyzed to a huge advantage. The most suitable handicap is the Exchange (a1 for b8). The Milov match showed though that it is tough for the computer because not only is it down the Exchange, but only Black can castle long, which is often advantageous with the b8 knight missing. So for a truly fair match, I would stipulate that Black cannot castle long (since White can't). Either this or the c7 pawn handicap (human getting White) are the most balanced and interesting handicaps for such a match in my opinion. There are other possibilities, such as knight odds vs. f7 odds for example, but the Exchange or the c7 handicap are the "cleanest".

[michiguel]

Who'se assessment is that there was no compensation? In addition to a pawn for the knight, Seamisch had an isolated doubled pawn in c. That is of course not 100% compensation but some, if we can trust R232a:

[d]r3k2r/p1pq1ppp/1pbp1n2/4p3/Q1P1P3/P1PBBP2/6PP/R3K1NR w KQkq - 0 13

Analysis by Rybka 2.3.2a 32-bit :

13.Qc2 Qe6 14.Rb1 0-0 15.Nh3 h6 16.0-0 Rad8 17.Be2 Nh5 18.Rfd1 Qg6 19.Bf1
+- (1.61) Depth: 9 00:00:01 57kN
+- (1.53) Depth: 16 00:01:04 3162kN

Besides, the extra piece is a bad bishop. The positional compensation is at least a full pawn if you consider also how destroyed is the pawn structure. Black should lose, but it should not resign just yet.

Miguel