Author: blass uri
Date: 04:51:37 07/31/00
Go up one level in this thread
On July 31, 2000 at 05:46:39, Ricardo Gibert wrote: >On July 31, 2000 at 05:33:42, Andreas Stabel wrote: > >>On July 31, 2000 at 04:14:42, Ricardo Gibert wrote: >> >>>On July 31, 2000 at 04:02:06, Ricardo Gibert wrote: >>> >>>>On July 31, 2000 at 03:32:31, Ricardo Gibert wrote: >>>> >>>>>On July 31, 2000 at 02:25:37, Poschmann wrote: >>>>> >>>>>>In a magazine I found the following position. It should be a draw ? >>>>>>Unfortunately I don't have the following issue of the magazine with the >>>>>>solution. >>>>>>It is a 6-piece-endgame. I tried to solve it with the help of Fritz6 >>>>>>(without tablebases), but I can't. >>>>>> >>>>>>[D]K7/8/4k3/1R1R4/8/8/p7/7r w - - >>>>>> >>>>>>I had the following to ideas: >>>>>>a) Go to a 5-piece-endgame: >>>>>>1. Re5+ Kf6 2. Rf5+ Kg6 3. Rg5+ Kh6 4. Rh5+ Rxh5 5. Rb6+ Kg5 6. Ra6 Rh2 >>>>>> >>>>>>b) Allow Black to promote the pawn: >>>>>>... 4. Rge5 a1=Q+ 5. Ra5 >>>>>> >>>>>>I think in both cases White loses the game. But I can't proof it without >>>>>>tablebases. >>>>>>- Can somebody with the 5-piece-tablebases proof position a) >>>>>>- Are some 6-piece-tablebases available to proof position b) without a pawn or >>>>>> the initial position with one pawn. >>>>>>- Is there somebody who knows the initial position and its solution ? >>>>>> >>>>>>Thank you >>>>>>Ralf Poschmann >>>>> >>>>>I think the basic idea may be something like this: >>>>> >>>>>1.Re5 Kf6 2.Ra5 a1Q 3.Rb5 Qd4 4.Rb6 Qxb6 5.Rf5 Ke7 6.Rf7 Kd8 7.Rf8 Kc7 8.Rf7 Kc8 >>>>> 9.Rc7 >>>>> >>>>>I'm doing this from work (night shift), so I didn't have time to elaborate nor >>>>>check my analysis. If it isn't right, maybe it will give you the ideas you need >>>>>to figure it out for yourself. Good luck! >>>> >>>>Oops! 3...Rh8 improves. It looks like I have to push the K all the way over to >>>>h6 after all: 2.Rf5 Kg6 3.Rg5 Kh6 4. Ra5 a1Q 5. Rb5 Qd4 (5...Qh8 6.Rb8) 6.Rb6 >>>>Qxb6 7.Rh5 Kg7 8.Rh7 Kf8 9. Rh8 Ke7 10.Rh7 Kd8 (10...Kd6 is a real can of worms >>>>I'll let you work out for now. I have to get back to work!) 11.Kc7 Rh7 12.Kc8 >>>>Rc7 >>> >>>Aha! I think I've fixed it now. 10..Kd6 11.Rh6 Kc5 12.Rh5 Kc4 wins, but 9.Rf7 >>>draws. Back to work again! >> >>Crafty finds the draw: >>14-> 44.43 0.00 1. Re5+ Kd6 2. Rbd5+ Kc6 3. Rc5+ Kb6 >> 4. Rb5+ Ka6 5. Ra5+ Kb6 6. Reb5+ Kc6 >> 7. Rxa2 <EGTB> >> >>Regards >>Andreas Stabel > >It seems to, but unfortunately the PV it gives is not very enlightning. 1...Kf6 >is the critical line. After 1...Kd6, could analysis should stop right then and >there with obvious draw. > >Feed the position after 1.Re5 Kf6 2.Rf5 Kg6 3.Rg5 Kh6 to crafty and see what it >says. Crafty can see the right moves Ra5 a1=Q Rb5 but you do not need to see it in a game because crafty is going to let you a simple perpetual check after Re5+ Kf6 Rf5+ Ke6 or maybe even Re5+ Kd6(when I start a game against Crafty with white from the position that was posted the game is Re5+ Kf6 Rf5+ Ke6 when the ke6 is because of retaining hash tables because without learniong from previous search crafty plays Kg6 and I guess that it even may play after Re5+ Kd6 if it could learn from previous positions). Uri
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