Author: Robert Hyatt
Date: 19:50:05 03/07/02
Go up one level in this thread
On March 07, 2002 at 22:45:55, Dieter Buerssner wrote:
>[D] 5b1k/3R4/5P2/p1rB4/8/8/6K1/8 b - -
>
>I think, this is an interesting position. It is from an ICC game of Shredder 6
>vs. Yace. Yace moved a4? and lost fast after this. I have looked at some
>variations, and the natural looking move a4 indeed seems to be a loss, while Rb5
>probably holds the draw.
>
>Perhaps I am too naive, but when I watched this game, I first was confident,
>that it should be a very easy draw. My (stupid?) reasoning was: A computer will
>not lose KRBKR (when he does not see the exceptional win fast). The position
>here is KRBPKRBP. The Bs are of opposite color. So, I thought, it should allways
>be possible, to sac one B for a P, and have an easy draw. Well, I was totally
>wrong, and so was the knowledge I coded into my engine.
>
>How long does your engine need, to avoid a4? How long does it need, to see a
>convincing winning score after a4? (Kg3 is a forced win, other moves perhaps,
>too).
>
>Regards,
>Dieter
Crafty decides a4 is not so good pretty quickly (on my laptop here)...
9-> 2.79 1.39 1. ... a4 2. Kh3 a3 3. Kg4 Ra5 4. Ba2
Rb5 5. Kf4 Bc5
10 4.43 -- 1. ... a4
10 6.90 1.97 1. ... a4 2. Kf3 Rc1 3. Kf4 Rf1+ 4.
Kg5 Rg1+ 5. Kf5 Bc5 6. Bc4 a3 7. Ke6
10 16.04 1.51 1. ... Rb5 2. Rd8 Kh7 3. Be4+ Kg8 4.
Rd7 Rb2+ 5. Kf3 Rb6 6. Bh7+ Kh8 7.
Rf7 Rb3+ 8. Kf4 a4
10-> 16.88 1.51 1. ... Rb5 2. Rd8 Kh7 3. Be4+ Kg8 4.
Rd7 Rb2+ 5. Kf3 Rb6 6. Bh7+ Kh8 7.
Rf7 Rb3+ 8. Kf4 a4
11 26.87 1.45 1. ... Rb5 2. Rd8 Kh7 3. Bc6 Rg5+ 4.
Kh3 Rg8 5. Be4+ Kh6 6. f7 Rh8 7. Kg3
Kg7 8. Rd7
11-> 30.40 1.45 1. ... Rb5 2. Rd8 Kh7 3. Bc6 Rg5+ 4.
Kh3 Rg8 5. Be4+ Kh6 6. f7 Rh8 7. Kg3
Kg7 8. Rd7
12 50.10 1.45 1. ... Rb5 2. Rd8 Kh7 3. Be4+ Kg8 4.
Rd7 Rb2+ 5. Kg3 Rb6 6. Bd5+ Kh8 7.
Rf7 Bc5 8. Kf4 a4
12-> 58.63 1.45 1. ... Rb5 2. Rd8 Kh7 3. Be4+ Kg8 4.
Rd7 Rb2+ 5. Kg3 Rb6 6. Bd5+ Kh8 7.
Rf7 Bc5 8. Kf4 a4
If you force a4 and let it search for white:
(2) 7-> 0.37 1.57 2. Kf3 a3 3. Ke4 Rc1 4. Kf5 Rf1+ 5.
Ke6 Re1+ 6. Kf5
8 0.57 1.48 2. Kf3 Rc1 3. Kf4 Rf1+ 4. Kg5 Rg1+
5. Kh5 Rf1 6. Kg6 a3
(4) 8-> 1.33 1.48 2. Kf3 Rc1 3. Kf4 Rf1+ 4. Kg5 Rg1+
5. Kh5 Rf1 6. Kg6 a3
9 1.80 ++ 2. Kf3!!
(3) 9-> 2.80 1.87 2. Kf3 Rc1 3. Kf4 Rf1+ 4. Kg5 Rg1+
5. Kh5 Rf1 6. Kg6 a3
(2) 10 4.68 1.68 2. Kf3 Ra5 3. Be4 Rh5 4. Kg4 Rh6 5.
Kf5 Rh7 6. f7 Rh5+ 7. Kg4 Re5
10-> 9.65 1.68 2. Kf3 Ra5 3. Be4 Rh5 4. Kg4 Rh6 5.
Kf5 Rh7 6. f7 Rh5+ 7. Kg4 Re5
11 11.27 ++ 2. Kf3!!
11 15.41 2.18 2. Kf3 Rc1 3. Kf4 Rf1+ 4. Kg5 Re1 5.
Kg6 Rg1+ 6. Kf7 Bc5 7. Rd8+ Kh7 8.
Be4+ Kh6 9. Ke6
11-> 19.99 2.18 2. Kf3 Rc1 3. Kf4 Rf1+ 4. Kg5 Re1 5.
Kg6 Rg1+ 6. Kf7 Bc5 7. Rd8+ Kh7 8.
Be4+ Kh6 9. Ke6
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