Author: Enrique Irazoqui
Date: 15:49:31 06/07/00
Go up one level in this thread
On June 07, 2000 at 18:23:59, Jorge Pichard wrote: >On June 07, 2000 at 17:22:58, Simon Finn wrote: > >>On June 07, 2000 at 16:01:30, Charlie GOLD wrote: >> >>>On June 07, 2000 at 14:47:53, Enrique Irazoqui wrote: >>> >>>>On June 07, 2000 at 13:55:38, Simon Finn wrote: >>>> >>>>>On June 07, 2000 at 13:46:29, Simon Finn wrote: >>>>> >>>>>>>>Interesting position, but is black forced to take from h6 (gxh6)? May be -Kc8 >>>>>>>>is better? I think that black loses in all variations. >>>>>>> I think that black loses in all variations. >>>>>> >>>>>>Jouni's suggestion of 1..Kc8! looks good to me. >>>>>>[D]8/1k4p1/3pP3/pP5P/8/8/1r5P/3K4 w - - 0 1 IF IT IS WHITE TO MOVE SURELY P-E7 WINS FOR WHITE and IF IT IS BLACK TO GO FIRST THEN BLACK WINS IN SEVERAL WAYS. CHARLIE >> >>It's White to move, but 1. e7 doesn't win. Black replies 1...Rb1+. >> >>Now 2. Kc2 allows 2... Re1 (and Black wins) while 2. Ke2 allows >>2... Rxb5, when Black can answer 3. e8Q with Re5+ (and Black wins again). >> >>So White has to run up the d-file >> >>2. Kd2 Rb2+ 3. Kd3 Rb3+ 4. Kd4 Rb4+ 5. Kd5 Rxb5+ 6. Kxd6 Rb6+ >> >>Now 7. Kd7 doesn't work - Black replies 7... Rb1 8. e8Q Rd1+ 9. Ke7 Re1+ >>and 7. Ke5 Rb1 is no better, so White has to run back down the d-file >> >>7. Kd5 Rb5+ 8. Kd4 Rb4+ 9. Kd3 Rb3+ >> >>Having captured the d6 pawn and returned, White can now cross the e-file >> >>10. Ke2 Rb2+ 11. Kf3 Rb3+ 12. Kf4 Rb4+ 13. Kf5 Rb5+ >> >>Now if White could only play 14. Kf6 Rb6+ 15. Kf7, he would win. >>Unfortunately, the black pawn on g7 prevents this. This means that >>he can make no futher progress (14. Kg6 Re5 wins for Black) so >>he has to take the draw with 14. Kf4. >> >>That's why 1. h6! gxh6? 2. e7 wins for White - it allows White to >>play Kf6 at the critical moment. >> >>>>>> >>>>>>After 1. h6 Kc8 2. h7 Rxh2 3. e7 Kd7 4. b6 Rxh7 5. b7 >>>>> >>>>>Sorry - that should read: >>>>> >>>>>1. h6 Kc8 2. h7 Rxh2 3. e7 Kd7 4. b6 Rxh7 5 e8Q+ Kxe8 6. b7 >>>> >>>>I don't think it works. 1.h6 Kc8 2. e7 Kd7 3. h7 Rxh2 4. b6 Rxh7 5. e8Q+ Kxe8 6. >>>>b7 Rh1+ 7. Kc2 Rh2+ 8. Kc3 Rh3+ 9. Kb2 Rh2+ 10. Ka3 then a4 and a5, and then the >>>>b pawn promotes. >> >>You're absolutely right - that line wins for White. My mistake. >> >>>> >>>>Enrique >>>> >>>> >>>>>and the following move-numbers are all of-by-one >>>>> >>>>>> (or 1. h6 Kc8 2. e7 Kd7 3. h7 Rxh2 4. b6 Rxh7 5. b7) >>>>>> >>>>>>Black can draw in two different ways: >>>>>> >>>>>>Either 5... Rh1+ 6. Kc2 Rh2+ 7. Kc3 Rh3+ 8. Kc2 Rh2+ with perpetual check >>>>>>(8. Kc4? Rh4+ and Rb4 wins for Black) >>>>>> >>>>>>Or 5... Rh6 6. b8Q+ Kf7 followed by ...d5 (unblocking the 6th rank) >>>>>>with a fortress draw. >> >>This is inaccurate too. >> >>After 1. h6 Kc8 2. h7 Rxh2 3. e7 Kd7 4. b6 Rxh7 5 e8Q+ Kxe8 >>6. b7 Rh6? 7. b8Q+ Kf7 White can blockade the d-pawn by 8. Qb7+ Kf8 9. Qd5! >>(preventing ...d5), followed by capturing the a-pawn with his king, >>bringing the king to d8 and (I think) finally using mating threats >>to set up a zugzwang. >> >>However, I still think Black can draw - by playing 6...d5 instead of 6...Rh6 >> >>The critical line is now: >> >>1. h6 Kc8 2. h7 Rxh2 3. e7 Kd7 4. b6 Rxh7 5 e8Q+ Kxe8 6. b7 d5 7. b8Q+ Kf7 >> >>Black's rook is uncomfortable on h7, but if he has time to play Rh6 >>the position will be a fortress draw. I don't see how White can >>prevent this. For example: >> >>8. Qc7+ Kf8 9. Qc8+ Kf7 10. Qf5+ Kg8 11. Qxd5+ Kf8 12. Qf5+ Kg8 13. Qxa5 Rh6 >> >>and Black just keeps his king on one of the squares f7/f8/g8/h8/h7 >>while moving his rook between h6 and f6. >> >>Simon > > Hiarcs may not be the best Analystical program, but Anand who has plenty of >experience playing against Chess Programs, chose Hiarcs at the Advanced Chess >Tournament as his analystical software of choice. Has anybody tried to solve it >with Hiarcs yet? I tried a couple of years ago with Hiarcs 6 or 7 on a PII-400 and it didn't find 1.h6 in less than 15 minutes. Tiger on a PIII-600E with 128MB hash finds h6 after 216 seconds (!), but the eval is only +0.02. After 30 minutes it's already +0.96, but it doesn't show the line. Enrique >Pichard
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