Author: Robert Hyatt
Date: 13:09:42 10/26/98
Go up one level in this thread
On October 26, 1998 at 12:43:26, Bruce Moreland wrote:
>Here is the tail end of a game played between my program (Ferret) on a 533 mhz
>Alpha and Crafty on a dual 450 mhz Pentium II, at time control of 5 0, on ICC.
>
>My program got smoked in a K+P ending it traded into (apparently) voluntarily.
>
>One of the things you hear about if you talk to old-timers in this field is that
>the square of the pawn is a totally important evaluation term. I'm not sure who
>said it, but someone said that it's worth 100 Elo points. This was a long time
>ago, back when programs would get killed in endings routinely, but I get the
>idea that this wisdom hasn't been re-evaluated much since then. It is my
>opinion that square of the pawn is worth almost nothing in practical play, since
>the number of K+P endings that actually occur, with play still in them, seems to
>be approximately zero.
>
>This ending may prove to be a counter-example. I currently don't have this
>knowledge in my program. I'm going to stick it back in and see if it
>understands this ending better.
>
>I would be interested in knowing if anyone has any thoughts about this subject
>in general or this ending in particular.
>
>[White "Ferret"]
>[Black "Box"]
>[Result "0-1"]
>[ECO "C75"]
>[WhiteElo "2986"]
>[BlackElo "2969"]
>[Opening "Ruy Lopez: modern Steinitz defense"]
>[NIC "RL.11"]
>[Time "19:46:56"]
>[TimeControl "300+0"]
>[SetUp "1"]
>[FEN "8/6pp/4pk2/4p3/2PqP3/3Q2P1/4KP2/8 w - - 18 62"]
>
>62. Qxd4 exd4 63. f4 e5 64. c5 exf4 65. gxf4 h5 66. e5+ Ke6 67. Kd3 h4 68. c6
>g6 69. c7 Kd7 70. Kxd4 h3 71. Ke3 h2 {White resigns} 0-1
>
>--------------------------------
>
> a b c d e f g h
> +---+---+---+---+---+---+---+---+
>8 | |///| |///| |///| |///| 8
> +---+---+---+---+---+---+---+---+
>7 |///| |///| |///| |/p/| p | 7
> +---+---+---+---+---+---+---+---+
>6 | |///| |///| p |/k/| |///| 6
> +---+---+---+---+---+---+---+---+
>5 |///| |///| |/p/| |///| | 5
> +---+---+---+---+---+---+---+---+
>4 | |///| P |/q/| P |///| |///| 4
> +---+---+---+---+---+---+---+---+
>3 |///| |///| Q |///| |/P/| | 3
> +---+---+---+---+---+---+---+---+
>2 | |///| |///| K |/P/| |///| 2
> +---+---+---+---+---+---+---+---+
>1 |///| |///| |///| |///| | 1
> +---+---+---+---+---+---+---+---+
> a b c d e f g h
>
>8/6pp/4pk2/4p3/2PqP3/3Q2P1/4KP2/8 w - - 18 62
>
>White to move and lose. My program played 62. Qxd4, with a score of about +1,
>although the move apparently loses by force. I would be interested to know if
>other programs avoid 62. Qxd4. If white can safely avoid this move it should be
>better, I think.
>
>--------------------------------
>
> a b c d e f g h
> +---+---+---+---+---+---+---+---+
>8 | |///| |///| |///| |///| 8
> +---+---+---+---+---+---+---+---+
>7 |///| |///| |///| |/p/| p | 7
> +---+---+---+---+---+---+---+---+
>6 | |///| |///| p |/k/| |///| 6
> +---+---+---+---+---+---+---+---+
>5 |///| |///| |///| |///| | 5
> +---+---+---+---+---+---+---+---+
>4 | |///| P |/p/| P |///| |///| 4
> +---+---+---+---+---+---+---+---+
>3 |///| |///| |///| |/P/| | 3
> +---+---+---+---+---+---+---+---+
>2 | |///| |///| K |/P/| |///| 2
> +---+---+---+---+---+---+---+---+
>1 |///| |///| |///| |///| | 1
> +---+---+---+---+---+---+---+---+
> a b c d e f g h
>
>8/6pp/4pk2/8/2PpP3/6P1/4KP2/8 w - - 0 63
>
>White to move. Here is the positions with the queens off, if this helps anyone.
> I think white is lost already here.
>
>--------------------------------
>
> a b c d e f g h
> +---+---+---+---+---+---+---+---+
>8 | |///| |///| |///| |///| 8
> +---+---+---+---+---+---+---+---+
>7 |///| |///| |///| |/p/| | 7
> +---+---+---+---+---+---+---+---+
>6 | |///| |///| |/k/| |///| 6
> +---+---+---+---+---+---+---+---+
>5 |///| |/P/| |///| |///| p | 5
> +---+---+---+---+---+---+---+---+
>4 | |///| |/p/| P |/P/| |///| 4
> +---+---+---+---+---+---+---+---+
>3 |///| |///| |///| |///| | 3
> +---+---+---+---+---+---+---+---+
>2 | |///| |///| K |///| |///| 2
> +---+---+---+---+---+---+---+---+
>1 |///| |///| |///| |///| | 1
> +---+---+---+---+---+---+---+---+
> a b c d e f g h
>
>8/6p1/5k2/2P4p/3pPP2/8/4K3/8 w - - 0 66
>
>White to move is completely lost. Mine figures this out after a while, but it
>takes too long, in my opinion (over a minute on a P6/200 to really start to
>crater). I'd be interested in knowing if anyone knows they are dead quickly.
>
>Thanks,
>
>bruce
In this last position I see black is winning very quickly. ie -1.5 in about
a second... and it drops every iteration after that... -2, etc...
I would probably play Qxd4 in the original position, however, based on a
quick check...
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