Author: Ricardo Gibert
Date: 02:37:46 09/26/00
Go up one level in this thread
On September 26, 2000 at 04:39:06, Stephen A. Boak wrote:
>Here's the promised look at the Deep Thought - Fishbein game, where Fishbein
>eventually lost the endgame with KR v KRB held by Deep Thought.
>
>Deep Thought - Fishbein,A [C69]
>Los Angeles, California, 1988
>
>{Steve Boak move notes, assisted by Fritz6a (plus 5-piece tablebases)}
>
>1.e4 C69: Ruy Lopez: Exchange Variation with 5 0-0 f6 1...e5 2.Nf3 Nc6 3.Bb5 a6
>4.Bxc6 dxc6 5.0-0 f6 6.d4 exd4 7.Nxd4 c5 8.Ne2 Qxd1 9.Rxd1 Bd7 10.Bf4 0-0-0
>11.c4 Ne7 12.Nbc3 Re8 13.Be3 Nc6 14.Rd2 Ne5 15.b3 h5 16.h3 b6 17.Nd5 Bc6 18.a4
>a5 19.Nec3 Kb7 20.Nb5 Bxb5 21.axb5 Bd6 22.f3 Ra8 23.f4 Nf7 24.Kf2 Rhe8 25.Kf3
>Bf8 26.Nc3 Nd6 27.Rd5 g6 28.g4 hxg4+ 29.hxg4 Bg7 30.f5 gxf5 31.gxf5 Rh8 32.Bf4
>Rh3+ 33.Bg3 Rg8 34.Rd3 Bf8 35.Kg2 Rh4 36.Re1 Rhg4 37.Kh3 a4 [37...Nf7!] 38.bxa4
>R8g7?? 1. ± (1.00): 38...R4g5 39.Nd5 Bg7 40.Nf4 Nxc4 41.Ne6 Ne5 42.Rd5 Rh5+
>43.Kg2
>2. ± (1.09): 38...Nxc4 39.Nd5 Ne5 40.Bxe5 fxe5 41.Nf6 Rg1 42.Rxg1 Rxg1 43.Rd5
>39.Bh4 Nxc4? 1. +- (1.53): 39...Rxh4+ 40.Kxh4 Nxc4 41.Nd5 Bd6 42.Kh3 Nb2 43.Ra3
>Nc4 44.Rb3
>2. +- (1.94): 39...Be7 40.Nd5 Nxc4 41.Bxf6 Bxf6 42.Nxf6 R4g5 43.Rd7 Rxd7 44.Nxd7
>40.Bxf6 White has a 2-point edge, per Fritz6a. 40...Rg8 41.e5 Bh6 42.Nd5 Bf4
>43.Rf3 Bxe5 44.Rxe5 1. +- (1.78): 44.Rxe5 Nxe5 45.Bxe5 Re4 46.Re3 Rxa4 47.Nxc7
>Rg5 48.Rf3 Re4
>2. ² (0.28): 44.a5 Nd2 45.a6+ Ka7 46.Rfe3 Bf4 47.Ne7 Rg3+ 48.Kh4 R8g4+
>3. = (-0.12): 44.Rd3 Bd6 45.Rf1 c6 46.Ne7 Rg3+ 47.Rxg3 Rxg3+ 48.Kh4 cxb5
>4. = (0.00): 44.Bxe5 Nxe5 45.Rxe5 Rg1 46.Kh2 R8g2+ 47.Kh3 Rg8 44...Nxe5 45.Bxe5
>R4g5 46.Bg3 c4 47.Nc3 Rh5+ 48.Kg2 Rgg5 49.f6 Rf5 50.Re3 Rxf6 51.Re7 Rff5
>52.Rxc7+ Ka8 53.a5 Fritz6a believes there are many much better moves, preserving
>approximately a 3-point edge for White. But Deep Thought gives back 2-points,
>keeping only a 1-point White edge! Fritz6a examples of better moves:
>1. +- (3.03): 53.Rc6 Rhg5
>2. +- (2.91): 53.Ne4
>3. +- (2.75): 53.Rc8+ Ka7 54.Ne4
>4. +- (2.59): 53.Rxc4 Rc5 54.Rxc5 Rxc5 55.Be1 Kb7 56.Kf3 Rc8 57.Bd2 Rd8
>5. +- (2.53): 53.Re7 53...Rxb5 54.Nxb5 Rxb5 55.axb6 Rxb6 56.Bf4 Rb3 57.Kf2 Rb7
>58.Rxc4 With this capture, Deep Thought enters a tablebase draw. 58...Rb2+
>59.Ke3 Kb7 60.Ke4 Rb5 61.Be3 Rh5 62.Bd4 Rg5 63.Be5 Kb6 64.Kd5 Kb5 65.Rc8 Rg6
>66.Rc5+ Kb6 67.Rc2 Rh6 68.Rb2+ Ka6 69.Bd6 Rh5+?? Oops! Fishbein enters a
>tablebase loss position (Black gets mated in 13 moves!). Only Ka5! keeps a
>tablebase draw. Somehow Deep Thought got a position (obviously Fishbein choices
>helped lead to this point--but would such a knife-edge juncture have occurred
>for the human sooner or later anyway?) where there was only one move for the
>human to hold the draw, and Fishbein calculated or guessed wrong. 70.Kc6 Rg5
>71.Rb3 Rh5 72.Rb1 non-optimal: mates in 13; Rb1 mates in 11. 72...Rg5 73.Rb2 Rh5
>74.Rb8 Rh7 75.Bf8 Ka7 returns the favor with a non-optimal defense: Rf7 lasts
>longest (mate in 9), whereas text allows mate in 7. 76.Rb3 Ka8 77.Re3 Rb7 78.Re4
>Rf7 79.Re8+ Ka7 80.Bc5+ Ka6 81.Ra8+ mating after 82...Ra7 Rxa7++ 1-0
>
>Bottom line thoughts (calculations from Fritz6a)--Fishbein (an IM at the time)
>did very well against the monster computer, Deep Thought. He was struggling in
>the opening (down 0.4 to 0.5 pawns at times) and middlegame, but somehow hung in
>there with the machine.
>
>On move 37 Fishbein missed Nf7! which would have left him down a mere and
>manageable 1/5 or 1/4 pawn. On move 53, Deep Thought strangely played a5?,
>giving back about 2/3 of its approx 3-point advantage. Fishbein kept up the
>strugggle/complications and obtained an underdog book draw KR v KRB by move 58,
>which he held as late as move 68.
>
>Then Fishbein slipped into a mate in 13 lost position, after which Deep Thought
>played sub-optimally at one point (losing 2 moves toward shortest mate).
>Ironically, Fishbein played sub-optimally once thereafter, giving back Deep
>Thought the 2 moves toward mate.
>
>I have heard that Fritz6a doesn't handle tablebases perfectly in some instances.
> I don't know if there were any programming glitches in the above situations,
>but I think the basic story is sound.
>
>Conclusion (my own): it is not an easy draw for even a strong human to hold
>(such as IM Fishbein), especially when the clock is ticking and potential 2nd
>time control or sudden death final time control may be looming. Missing a
>13-move mate, as Fishbein did, is not unforgiveable for a human, even an IM!
>
>It was enjoyable to compare a strong modern program (Fritz6a) moves with those
>of a mega-machine competitor of 11-12 years ago. It would have been nice to
>have the clock times available for both Fishbein and Deep Thought, to allow
>better comparison with Fritz6a move selections under similar time constraints,
>but alas I lack that information.
>
>Thanks again, Ricardo, for posting the game score! Any additional thoughts
>after the above analysis?
>
>--Steve
I'm afraid I'm not prepared to contest the judgement of a program armed with
EGTBs. ;)
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