Author: Dann Corbit
Date: 16:48:17 05/12/00
Go up one level in this thread
On May 12, 2000 at 18:51:23, Ed Schröder wrote:
>On May 12, 2000 at 16:21:01, blass uri wrote:
>>[D]1r3nk1/3rb1p1/p2p1pP1/1p2p3/Pnq1P1R1/2N1B3/1PPR3P/2NQ3K w - - 0 1
>>
>>This position is from the ssdf games(Junior5-Junior6).
>>The evaluation was close to equality and suddenly Junior5 failed high and found
>>more than 1 pawn advantage for white.
>>
>>I post this position to demonstrate the fact that tactics is not only
>>sacrifices.
>>
>>Unfortunately tactical test positions are usually sacrifices.
>>
>>I am also not sure if there is only one good move for white.
>>White played in the game Rg2.
>>This is a good move with the idea to give mate by Rh4 and Qh5 but I am not sure
>>if this is the only good move and it is possible that axb5 and after it Rg2 also
>>give the same result(I did not check it)
>>
>>The point is not to find Rg2 but to find a significant change in the evaluation.
>>
>>How much do programs need to fail high?
>>
>>I think it is a good idea to generate a tactical test suite based on positions
>>from practical games and not based on finding sacrifices.
>>
>>In order to do it we need to analyze many games and find cases when there is a
>>significant change in the evaluation.
>>
>>
>>Uri
>
>The latest Rebel running under EPD2DIAG:
>
>00:01 07.00 0.44 1.axb5 axb5 2.Nd5 Nxd5 3.exd5 Qc7 4.Qf1 Bd8 5.Qh3
>00:03 08.00 0.37 1.axb5 axb5 2.Nd3 Ra8 3.Nxb4 Qxb4 4.Qc1 Qc4 5.Nd5 Ra2
>00:11 09.00 0.44 1.axb5 axb5 2.Nd3 Ra8 3.Rf2 Nc6 4.Nd5 Qa2
>00:23 09.15 0.44 1.Rdg2
>00:28 09.15 0.75 1.Rdg2 d5 2.exd5 Nxd5 3.Rxc4 Nxe3 4.Qf3 Nxc4 5.axb5 axb5
>6.Nd3
>00:47 10.00 0.80 1.Rdg2 d5 2.exd5 Qc7 3.axb5 axb5 4.Rh4 f5 5.Rh5 Bc5 6.Bxc5
>Qxc5
>01:23 11.00 0.68 1.Rdg2 d5 2.exd5 Qc8
>01:37 11.01 0.80 1.axb5 axb5 2.Rdg2 d5 3.exd5 Qc7 4.Rh4 f5 5.Rh5 Bc5 6.Bxc5
>02:06 12.00 0.84 1.axb5 axb5 2.Rdg2 d5 3.exd5 Nxd5 4.Rxc4 Nxe3 5.Qxd7 Nxd7
>6.Rc7 Nxg2 7.Rxd7 b4 8.Rxe7 bxc3
>03:54 13.00 0.89 1.axb5 axb5 2.Rdg2 d5 3.Rh4 f5 4.Rh3 Rd6 5.exf5 Rf6
>04:35 13.01 0.98 1.Rdg2 d5 2.exd5 Qc8 3.Qf3 Qd8 4.axb5 Nxd5 5.Nxd5 Rxd5 6.b6
Absolutely incredible!
Amy finds it after 25 minutes, but (for all intents and purposes) hangs in the
research:
GamePhase: Opening
It Time Score principal Variation
7 1.2 -0.144 1. Nd5 Nxd5 2. exd5 Qc7 3. axb5 axb5 4. Qe2 Rdd8
7 1.4 +++ 1. axb5
7 1.5 -0.032 1. axb5 axb5 2. Nd3 Ra8 3. Nxb4 Qxb4 4. Nd5 Qxb2
7 2.3 -0.032 1. axb5 axb5 2. Nd3 Ra8 3. Nxb4 Qxb4 4. Nd5 Qxb2
8 3.3 -0.016 1. axb5 axb5 2. Nd5 Nxd5 3. exd5 Qc7 4. Kg1 Ra8 5. Nd3
8 5.5 -0.016 1. axb5 axb5 2. Nd5 Nxd5 3. exd5 Qc7 4. Kg1 Ra8 5. Nd3
9 9.6 -0.080 1. axb5 axb5 2. Nd3 Ra8 3. Nxb4 Qxb4 4. Rf2 d5 5. exd5
Qxb2
9 15.6 -0.080 1. axb5 axb5 2. Nd3 Ra8 3. Nxb4 Qxb4 4. Rf2 d5 5. exd5
Qxb2
10 23.9 +0.112 1. axb5 axb5 2. Nd3 Ra8 3. Nxb4 Qxb4 4. Rf2 Qc4 5. Nd5
Qc6 6. Kg1
10 31.5 +0.112 1. axb5 axb5 2. Nd3 Ra8 3. Nxb4 Qxb4 4. Rf2 Qc4 5. Nd5
Qc6 6. Kg1
11 1:00 +0.064 1. axb5 axb5 2. Nd3 Nxd3 3. Rxd3 Qc8 4. Kg1 Qe8 5. Rd2 b4
6. Nd5 Nxg6
11 1:22 +0.064 1. axb5 axb5 2. Nd3 Nxd3 3. Rxd3 Qc8 4. Kg1 Qe8 5. Rd2 b4
6. Nd5 Nxg6
12 2:39 +0.192 1. axb5 axb5 2. Nd3 Nxd3 3. Rxd3 Qc8 4. Nd5 Qe8 5. Rg1
Rbd8 6. Nb6 Ra7 7. Nd5
12 3:22 +0.192 1. axb5 axb5 2. Nd3 Nxd3 3. Rxd3 Qc8 4. Nd5 Qe8 5. Rg1
Rbd8 6. Nb6 Ra7 7. Nd5
13 6:17 +0.144 1. axb5 axb5 2. Nd3 Nxd3 3. cxd3 Qe6 4. Rg1 Bd8 5. Rdg2
Rc7 6. Nd5 Rc6 7. Rc2 Rbc8
13 8:13 +0.144 1. axb5 axb5 2. Nd3 Nxd3 3. cxd3 Qe6 4. Rg1 Bd8 5. Rdg2
Rc7 6. Nd5 Rc6 7. Rc2 Rbc8
14 16:42 +0.176 1. axb5 axb5 2. Nd3 Nxd3 3. Rxd3 Qc8
14 87:07 +++ 1. Rdg2
Like the energizer bunny, it keeps going and going and going...
Which brings up a point...
I have seen some chess engines do something silly. The have finished a ply
(say, for instance, ply 14 side to move) and do a fail high. Then *instead* of
choosing the move that failed high, they stick with the one that was
completed!!! {in this case, the engine might still play axb5 -- though I doubt
that Amy has this fault}.
Why would anyone want to do that? It does not make any sense to me.
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