Author: Simon Finn
Date: 16:47:36 06/30/00
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On June 30, 2000 at 17:03:01, ujecrh wrote: >>My guess is white moves Rc4+ and then it's around and around the mulberry >>bush... > >In fact that is maybe not so obvious. I have only 4men, and run the position >after a possible 'a' pawn sacrifice and: > >White(1): setboard 8/8/8/8/P3k3/8/1KR5/3q4 b - - 0 1 >Black(1): time 1/60 >1 moves/60 minutes primary time control >1 moves/60 minutes secondary time control >Black(1): go >end-game phase > clearing hash tables > time surplus 0.00 time limit 60:00 (30:00) > nss depth time score variation (1) > 8 1.20 ++ 1. ... Kd4!! > 8 1.57 4.78 1. ... Kd4 2. Rh2 Kc5 3. Ka3 Qd3+ 4. > Ka2 Qc4+ 5. Kb1 Qb4+ 6. Kc1 Qa3+ 7. > Rb2 Qxa4 > 8-> 1.57 4.78 1. ... Kd4 2. Rh2 Kc5 3. Ka3 Qd3+ 4. > Ka2 Qc4+ 5. Kb1 Qb4+ 6. Kc1 Qa3+ 7. > Rb2 Qxa4 > 9 1.99 4.95 1. ... Kd4 2. Rh2 Kc5 3. Ka3 Qc1+ 4. > Ka2 Qf4 5. Rh3 Kb4 6. Rb3+ Kxa4 7. > Kb2 > 9-> 3.36 4.95 1. ... Kd4 2. Rh2 Kc5 3. Ka3 Qc1+ 4. > Ka2 Qf4 5. Rh3 Kb4 6. Rb3+ Kxa4 7. > Kb2 > 10 4.29 ++ 1. ... Kd4!! > 10 9.72 Mat32 1. ... Kd4 2. Rg2 Kc4 3. Rh2 Kc5 4. > Ka3 Qd3+ 5. Ka2 Qc4+ 6. Kb2 Qd4+ 7. > Kc1 Qxa4 <HT> > >This is always amazing to see things like mate in 32 ! :o) > >Ujecrh The position appears to be a draw, but only just. After 1. Rc4+ Kd3 2. Rc3+ Kd2 3. Rc8 Qh5 4. Rc2+ Kd1 5. Rc1+ Kd2 6. Rc2+ Kd3 7. Rc3+ Kd4 8. Rc4+ Kd5 Black's King gets driven back to d5, so it's simplest for Black to answer 1. Rc4+ with 1.. Kd5, giving the following position: [D]8/8/8/p2k4/2R5/1P6/1K6/3q4 w - - 0 1 Now Black's winning chances consist of either (1) Exchanging pawns to reach a winning QvR ending, or (2) Sacrificing the a-pawn to reach a winning QvR+P ending. To prevent plan (1), White should leave his Rook on c4, to anwer a4 with Rxa4. This allows Black to try plan (2). 2. Ka2 Qd2+ 3. Kb1 Qf2 4. Ka1 Qe2 5. Kb1 Qd2 6. Ka1 [D]8/8/8/p2k4/2R5/1P6/3q4/K7 b - - 0 1 6... a4 7. Rxa4 Qc3+ 8. Ka2 Qc2+ 9. Ka3 Qb1 [D]8/8/8/3k4/R7/KP6/8/1q6 b - - 0 1 If the Black king were on b5 rather than d5, Black would be winning, but here White can hold the draw with: 10. Ra5+ Kd4 (10 ... Kc6 11. b4 draws easily - the Black King can't cross the fifth rank) 11. b4 Qd3+ 12. Ka4 Qc2+ 13. Ka3 Qc3+ 14. Ka4 Qb2 15. Rc5 Qa2+ 16. Kb5 Qa7 [D]8/q7/8/1KR5/1P1k4/8/8/8 w - - 0 1 This seems to be the best that Black can achieve from the original position - he has driven the White King in front of the pawn which forces the White Rook to abandon its safe square on c5. Unfortunately the Rook always has at least one other safe square on the c-file, cutting off the Black King and holding the draw. For example: 17. Rc4+ Kd3 18. Rc1 Kd2 19. Rc5 Kd1 20. Rc4 Qb7+ 21. Ka5 Kd2 22. Rc5 = [D]8/1q6/8/K1R5/1P6/8/3k4/8 w - - 0 1 Black can't break the barrier on the c-file, so we get a fortress draw. Simon
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