Author: Robin Smith
Date: 14:45:16 01/27/99
I have been playing over some chess positions with my computer (Pentium 166) and have found some very strange behavior in the program Junior 5 in some endgames. strange position #1 white Kd5, Pb5, Pc6 black Ka2, Rb1 White to move wins easily with Kc5; but Junior wants to play c7??, thinking that this also wins (evaluation ~=+2.5 pawns). Only after a think of several minutes does it switch to Kc5, but not because it sees that c7? Rxb5+ draws, it is because it decides Kc5 is even better than +2.5 pawns. All of this wouldn't be all that odd since the draw involves a perpetual check, except that once Junior 5 plays c7 it INSTANTLY (less than 1 second) correctly sees the position is drawn! even stranger position #2 white Kd3 Ra2 black Kd1 Pe2 Black to move, Junior wants to play Ke1, thinking that white will be mated in 7 after Rxe2+; but e1=N+ draws! No mater how long Junior thinks it doesn't see the underpromotion. strangest position #3 white Kf6, Be5 black Kh8, Bg8, Pg6 White to move can mate on the move with Kxg6 mate, but Junior 5 shuns both the mate and the win of the pawn, preferring to draw the game with some silly bishop move. This occurs no matter how long you let Junior 5 think! This bug must have to do with Junior thinking that it "knows" B vs. B is "insufficient material" and thus it shuns taking the pawn in the hopes that it might find a win by keeping the pawn on the board. Incredible! For the record, I still really like the program. Most of the time it's play is very strong, unlike some other programs it never seems to crash and the user interface is very good (though I would like to see EPD support). Any comments from Junior 5's programmer?
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