Author: Uri Blass
Date: 10:25:39 07/24/01
Go up one level in this thread
On July 24, 2001 at 09:48:29, Ian Kennedy wrote:
>In a recent test game against my computer (which was Black), the following
>postion arose:
>
>[D] 4Nr2/2QR1pkp/4p1p1/8/1p6/r3q1NP/6PK/8 b - - 0 0
>
>I'd gone for a cheapo draw attempt hoping to fool it into playing Rxe8. No such
>luck, it played Kh8 and went on to win.
>
>When I went back to the position after 31. ... Rxe8 to see if there was a draw
>to be had, I was surprised to find its a very forced win for White. But neither
>Crafty or Fritz can see the mate all in one go, even though this line I worked
>out in Fritz has 15 checks out of 20 moves before the final mate:
>
>(31... Rxe8?? 32. Rxf7+ Kh6 33. Rxh7+ Kg5 34. h4+ Kg4
>35. Qc4+ Qf4 36. Qe2+ Rf3 37. gxf3+ Qxf3 38. Qe1 Qf4 39. Qd1+ Qf3 40. Qg1 Qf4
>41. Qg2 Qf3 42. Qh3+ Kf4 43. Rf7+ Ke5 44. Rxf3 Kd6 45. Rd3+ Kc6 46. Qg2+ Kc7
>47. Qc2+ Kb8 48. Qc5 Rf8 49. Qxb4+ Kc7 50. Qc5+ Kb7 51. Rd7+ Ka6 52. Ra7# {
>(Fritz 5)})
>
>Yet Crafty on my PC is only showing +3.65 after an hour or so. Maybe there is
>some inaccuracy in the above variation?
The first move for black that is not obviously forced is 38...Qf4
Here are some non trivial mate to find before you can claim mate in 21
1)After 38...e5
2)After 38...g5
3)After 38...Rc8
4)After 40...Rd8
5)After 40...Re7
6)After 44...Re7
7)After 45...Ke7
I do not know if there is a forced mate in 21 but you have to work in order to
prove it by a tree and check every legal move of black in every position in
order to see if the computer find a forced mate after it.
Uri
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