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Subject: Re: Great rook sac

Author: Ed Schröder

Date: 03:55:25 01/30/00

Go up one level in this thread


On January 30, 2000 at 06:50:55, David Blackman wrote:

>On January 30, 2000 at 04:07:51, allan johnson wrote:
>
>>On January 30, 2000 at 04:05:13, allan johnson wrote:
>>
>>>How many programmes out there can find the wonderful rook sac in the position
>>>below? Neither Rebel Century nor Fritz 5.32 got close within 10 minutes on
>>>a Celeron 433 128 mb ram.It comes from a  game between G Sax  and J Kestler
>>>Nice 1974.
>[D] r1b1k3/2q1ppb1/2p2n2/3p1PBB/2nP3P/Pp5N/1P2Q1P1/2KR3R b--
>>> If someone thinks the sac is suss please let me know.
>>>1... Rxa3 2pxa3 Qa5 3Rd3 Qxa3ch 4Kb1 Bxf5. At this point both Rebel and Fritz
>>>were acknowledging white's position is lost.
>
>I wonder if 3 Rh-f1 might last a little longer? I can't see what Rd3 is supposed
>to achieve.
>
>But apart from that it just looks like a typical position designed to make null
>move look bad. Fritz is a famous null-mover. Rebel is claimed not to use
>standard recursive null move, but probably uses some other pruning scheme that
>has the same problem here. Junior is supposed to do no null moves for the first
>few moves. Perhaps it would understand this.

4:24 for Rebel Century 1.2, here is the log

Ed

----------------

Thinking....

  +---+---+---+---+---+---+---+---+  RXA3.EPD - Player
8 | *R|   | *B|   | *K|   |   |   |
  +---+---+---+---+---+---+---+---+  00:00:00      00:00:00
7 |   |   | *Q|   | *p| *p| *B|   |
  +---+---+---+---+---+---+---+---+
6 |   |   | *p|   |   | *N|   |   |  Time          infinite
  +---+---+---+---+---+---+---+---+  Hash          60 Mb
5 |   |   |   | *p|   | p | B | B |  Engine        Rebel Century
  +---+---+---+---+---+---+---+---+  Personality   Rebel Century
4 |   |   | *N| p |   |   |   | p |  anti-GM       Off
  +---+---+---+---+---+---+---+---+  Fast Eval.    On
3 | p | *p|   |   |   |   |   | N |  Fast Search   On
  +---+---+---+---+---+---+---+---+  Style         Normal
2 |   | p |   |   | Q |   | p |   |  Strength      Strongest
  +---+---+---+---+---+---+---+---+  Search        Normal Search
1 |   |   | K | R |   |   |   | R |
  +---+---+---+---+---+---+---+---+
    a   b   c   d   e   f   g   h

r1b1k3/2q1ppb1/2p2n2/3p1PBB/2nP3P/Pp5N/1P2Q1P1/2KR3R b q -

[Event "?"]
[Site " White to move "]
[Date "2000.01.30"]
[Round "?"]
[White "Player"]
[Black "RXA3.EPD"]
[Result "*"]
[WhiteElo "?"]
[BlackElo "?"]
[FEN "r1b1k3/2q1ppb1/2p2n2/3p1PBB/2nP3P/Pp5N/1P2Q1P1/2KR3R b - - 0 1"]

1..*

00:00:00  1.00  -1.27   1..Nxh5 2.Qxh5 Bxf5
00:00:00  2.00  -1.43   1..Nxh5 2.Qxh5 Bxf5 3.Qe2
00:00:00  3.00  -1.49   1..Nxh5 2.Qxh5 Bxf5 3.Rdf1 Bg6 4.Qg4
00:00:00  4.00  -1.47   1..Nxh5 2.Qxh5 Bxf5 3.Rde1 e5 4.dxe5
                       Bxe5  (0)

00:00:00  5.00  -1.64   1..Nxh5 2.Qxh5 Bxf5 3.Rhe1 Be4 4.Re2
00:00:01  5.01  -1.61   1..Bxf5 2.Bxf6 Bxf6 3.Rdf1 Be4 4.Kd1
                       Bc2+ 5.Kc1  (0)

00:00:02  6.00  -1.27   1..Bxf5 2.Bf4 e5 3.dxe5 Nxh5 4.Qxh5
                       Be4 5.Qe2 Bxe5  (1)

00:00:04  7.00  -0.80   1..Bxf5 2.Bf4 Qa7 3.Bf3 Bc2 4.Rde1
                       Nxb2 5.Qxe7+ Qxe7 6.Rxe7+ Kxe7 7.Kxb2  (2)

00:00:05  7.01  -0.80   1..Nxh5
00:00:06  7.01  -0.04   1..Nxh5 2.Qxh5 Rxa3 3.bxa3 Qa5 4.Rd3
                       Qxa3+ 5.Kd1 Qa1+ 6.Bc1 Nb2+ 7.Ke2
                       Nxd3  (5)

00:00:09  8.00  -0.04   1..Nxh5 2.Qxh5 Rxa3 3.bxa3 Qa5 4.Rd3
                       Qxa3+ 5.Kd1 Qa1+ 6.Bc1 Nb2+ 7.Ke2
                       Nxd3  (6)

00:00:26  9.00  0.40   1..Nxh5 2.Qxh5 Rxa3 3.bxa3 Qa5 4.Rd3
                       Qxa3+ 5.Kd1 Qa1+ 6.Ke2 Qxh1 7.Rxb3  (12)

00:01:36 10.00  0.43   1..Nxh5 2.Rhe1 Nf6 3.Bxf6 Bxf6 4.Qg4
                       Kf8 5.Rd3 Qa5 6.Re2 c5  (39)

00:04:24 10.03  0.43   1..Rxa3
00:08:13 10.03  1.65   1..Rxa3 2.bxa3 Qa5 3.Bxf7+ Kxf7
                       4.Rd3 Qxa3+ 5.Kb1 Ne4 6.Qh5 Kf8
                       7.Bxe7+ Qxe7 8.Ng5 Nc3+  (264)


Positions                :     167.495.130
Nodes per second         :         234.587

Extensions (checks)      :      21.593.188 (-12%)
Extensions (captures)    :       2.253.981 (1%)
Extensions (king safety) :       1.677.657 (1%)
Extensions (on depth)    :       1.442.234 (0%)
Extensions (remaining)   :         727.392 (0%)
Extensions (total)       :      27.694.452 (16%)

Hash Table               : 2.092.048  2.285.887  (99%)
Average depth            : 16
Deepest depth            : 60




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