Author: Robert Hyatt
Date: 20:19:32 06/25/98
Go up one level in this thread
On June 25, 1998 at 21:45:15, Robert Hyatt wrote:
>On June 25, 1998 at 19:25:39, Bruce Moreland wrote:
>
>>
>>On June 25, 1998 at 16:18:29, Robert Hyatt wrote:
>>
>>>Bruce is doing some extension stuff that might well pick this up quickly,
>>>as Cray Blitz gets this right at 5 plies and 0 seconds, but the PV is quite
>>>long and has the horizon moves by white correct, and it realizes that black
>>>*has* to stop to capture each pawn that is offered, but it discovers that
>>>those moves are "singular" and it extends them quite deeply. I'm not yet
>>>doing singular extensions in crafty, so I don't catch this so quickly, but
>>>I'm starting to play with them again to see if I like the result.
>>
>>Nope, nothing weird here, just null move with maybe some conservative and
>>minimal pawn push extensions and some razoring.
>>
>>I find it in 9 plies, but it's +2 until 14 plies, at which point it goes up to
>>+5.
>>
>>If this contradicts anything in my original post on this, it's because I've
>>changed versions and machines (trivial version changes).
>>
>>bruce
>
>
>can you post your 9 ply PV? the problem I have at 9 plies is that white has
>a few threats of his own. Starting with h4 and black has to retake... then
>another pawn push that black has to take time out for. Without those, this is
>an easy position, but each white pawn push requires a capture by black or white
>gets a queen first. This is what hurts my search...
this is an interesting position. I just ran some analysis. First, here
is my 9 ply search:
9-> 0.25 -0.03 1. ... Ra3 2. Rxa3 bxa3 3. g4 Kd5 4.
g5 Kd6 5. h5 gxh5 6. Kh4
this is cute. Ra3 Rxa3 bxa3 are forced. g4 is cute as now black has
to do something besides go after the a-pawn, else g5 and h4 queens first.
Crafty understands the threatened promotion, so keeps the king in the square
of the potentially passed h-pawn...
within 9 plies, I obviously can't solve this.
here's additional searches, showing what I see. I don't understand this
until ply=12:
10 0.53 -- 1. ... Ra3
10 0.76 -0.51 1. ... Ra3 2. Rxa3 bxa3 3. g4 Kd5 4.
g5 e5 5. h5 gxh5 6. g6 Ke6 7. g7
10-> 0.77 -0.51 1. ... Ra3 2. Rxa3 bxa3 3. g4 Kd5 4.
g5 e5 5. h5 gxh5 6. g6 Ke6 7. g7
11 1.12 -0.71 1. ... Ra3 2. Rxa3 bxa3 3. g4 Kd5 4.
g5 e5 5. h5 gxh5 6. g6 Ke6 7. g7 Kf7
11-> 1.13 -0.71 1. ... Ra3 2. Rxa3 bxa3 3. g4 Kd5 4.
g5 e5 5. h5 gxh5 6. g6 Ke6 7. g7 Kf7
12 2.44 ++ 1. ... Ra3!!
12 4.17 2.46 1. ... Ra3 2. Rxa3 bxa3 3. h5 gxh5
4. Kh4 Kc3 5. Kxh5 Kb2 6. g4 fxg4 7.
Kh4 Kxa2 8. Kxg4
12-> 4.19 2.46 1. ... Ra3 2. Rxa3 bxa3 3. h5 gxh5
4. Kh4 Kc3 5. Kxh5 Kb2 6. g4 fxg4 7.
Kh4 Kxa2 8. Kxg4
big question is, now, how is Ferret seeing this at depth=9, because it
looks quite tricky for both sides to me. What is Crafty overlooking here?
Bob
This page took 0.01 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.