Author: Derek Mauro
Date: 11:35:06 03/23/01
Go up one level in this thread
On March 23, 2001 at 01:09:23, James T. Walker wrote: >On March 23, 2001 at 00:49:45, James T. Walker wrote: > >>On March 22, 2001 at 17:55:07, Derek Mauro wrote: >> >>>I'm no expert on computer chess, but I thought I'd call this to everyone's >>>attention. I was analyzing one of my recent games with Tiger (reg. and gambit), >>>and had a drawn position(I had black). >>> >>>[D]8/8/8/8/1n6/2K5/p7/6k1 w - - 0 111 >>> >>>For some reason, in the obvious draw, Tiger gives it -12 and wants to play >>>Kxb4?? even after like 20 minutes. All the programs seem to think its about -6 >>>or so, but they all play the correct move, the obvious Kb2. Is this a bug? >>>(The 4 piece tablebases will easily solve this bug, but this position is so >>>incredibly easy that I can't see why it would even need them.) >>> >>>This next position is also from the same game that all programs seem to have >>>trouble with, but I don't believe this is a bug. >>> >>>[D]8/1k6/2n5/8/6r1/p1K5/7R/8 b - - 0 87 >>> >>>Most programs want to play Nb4, but from there white can force a draw. I think >>>Ra4 is the correct move (Na5 might also work), but I'm not sure. I also fell to >>>the tempation of Nb4 during the game :( >>> >>>Derek >> >>Hello Derek, >>Can you post a line which gives white the draw after Nb4? It seems to me that >>black should still win this ending. What am I missing? >>Jim > >This is funny. The more I look at it the more I can't see how to win it either! >:-) >Jim The rest of the game went like this: 87... Nb4 88. Rh7+ Ka6 89. Kb3 a2 90. Rh6+ Kb5 91. Rh5+ Kb6 92. Rh6+ Kc5 93. Rh5+ Kd4 94. Rh1 Kd3 95. Rd1+ Ke2 96. Rh1 Kd2 97. Rh2+ Ke3 98. Rh3+ Kf2 99. Rh1 Rf4 100. Ra1 Ke2 101. Kc3 Re4 102. Rh1 Ke3 103. Re1+ Kf2 104. Ra1 Rg4 105. Kb3 Ke3 106. Kc3 Ke2 107. Rh1 Ke3 108. Re1+ Kf2 109. Ra1 1/2-1/2 Trading rooks on the 1st rank results in the position in the first diagram. All those moves are pretty much forced. There are a couple other moves in there, but none of them work (I think). There is no way to trade rooks closer to the promotion square, I already tried that. I think Ra4 was better, because it allows the knight to move and eventually attack the promotion square. Supporting a pawn from behind with a rook is also a basic principle. Very tough endgame!
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