Author: Robert Hyatt
Date: 18:45:10 05/12/00
Go up one level in this thread
On May 12, 2000 at 19:48:17, Dann Corbit wrote:
>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.
Rebel's move wasn't so incredible. It just liked Rdg2 very slightly more at
depth 13... we see many such tactical shots that are solved positionally (at
times for the wrong reason) by programs...
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