Difference between revisions of "Capture Extensions"

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(Created page with "'''Home * Search * Selectivity * Extensions * Capture Extensions''' '''Capture Extensions''' were used early in brute-force chess pr...")
 
 
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A lot of todays programs, more focused on [[Reductions|reductions]] rather than extensions in the [[Scout]] part of their [[Principal Variation Search|PVS]], most often don't reduce captures, which makes it a kind of implicit extension relative to reduced late [[Quiet Moves|quiet moves]]. It also seems worth a try to reduce even captures with negative SEE while performing [[Late Move Reductions|LMR]].  
 
A lot of todays programs, more focused on [[Reductions|reductions]] rather than extensions in the [[Scout]] part of their [[Principal Variation Search|PVS]], most often don't reduce captures, which makes it a kind of implicit extension relative to reduced late [[Quiet Moves|quiet moves]]. It also seems worth a try to reduce even captures with negative SEE while performing [[Late Move Reductions|LMR]].  
  
However, it seems important to extend captures if a transition to certain late endgames occurs. [[Ed Schroder|Ed Schröder]] for instance extends '''three''' [[Ply|plies]] in [[Rebel]] if entering the [[Pawn Endgame|pawn endgame]], and the static, [[Incremental Updates|incremental updated]] [[Score|score]] dominated by [[Material|material]] is not outside a +-3 pawn window around zero: The extension is very powerful, it will often avoid REBEL entering a lost ending and vice versa <ref>[http://www.top-5000.nl/authors/rebel/chess840.htm Programmer Corner - How Rebel Plays Chess] by [[Ed Schroder|Ed Schröder]], Extension Techniques: Endgame, [http://members.home.nl/matador/Inside%20Rebel.pdf pdf reprint]</ref>.  
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However, it seems important to extend captures if a transition to certain late endgames occurs. [[Ed Schroder|Ed Schröder]] for instance extends '''three''' [[Ply|plies]] in [[Rebel]] if entering the [[Pawn Endgame|pawn endgame]], and the static, [[Incremental Updates|incremental updated]] [[Score|score]] dominated by [[Material|material]] is not outside a +-3 pawn window around zero: The extension is very powerful, it will often avoid REBEL entering a lost ending and vice versa.  
  
 
=See also=
 
=See also=
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=External Links=
 
=External Links=
 
* [http://web.archive.org/web/20070607151732/www.brucemo.com/compchess/programming/extensions.htm Search Extension] from [[Bruce Moreland|Bruce Moreland's]] [http://web.archive.org/web/20070607231311/www.brucemo.com/compchess/programming/index.htm Programming Topics]
 
* [http://web.archive.org/web/20070607151732/www.brucemo.com/compchess/programming/extensions.htm Search Extension] from [[Bruce Moreland|Bruce Moreland's]] [http://web.archive.org/web/20070607231311/www.brucemo.com/compchess/programming/index.htm Programming Topics]
* [http://www.top-5000.nl/authors/rebel/chess840.htm Programmer Corner - How Rebel Plays Chess] by [[Ed Schroder|Ed Schröder]], [http://members.home.nl/matador/Inside%20Rebel.pdf pdf reprint]
 
  
 
=References=
 
=References=
 
<references />
 
<references />
 
 
'''[[Extensions|Up one Level]]'''
 
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Latest revision as of 22:29, 29 July 2019

Home * Search * Selectivity * Extensions * Capture Extensions

Capture Extensions were used early in brute-force chess programs to minimize some horizon effects. Due to the self-restricting nature of captures in Chess (max. 30 pieces may be captured per game), one may consider this a good idea. However, extending every capture was discarded by most programmers, and some constrains or conditions were applied, i.e. to extend only forced recaptures on the same target square.

Hans Berliner suggested to extend only those (re)captures, which restore the material balance at the root. Furthermore, capture extensions are often restricted to PV-nodes, or some programs assign fractional extensions to different kinds of captures, considering SEE, distance of target square to the opponent king, recapturing on the same square, and material balance as mentioned.

A lot of todays programs, more focused on reductions rather than extensions in the Scout part of their PVS, most often don't reduce captures, which makes it a kind of implicit extension relative to reduced late quiet moves. It also seems worth a try to reduce even captures with negative SEE while performing LMR.

However, it seems important to extend captures if a transition to certain late endgames occurs. Ed Schröder for instance extends three plies in Rebel if entering the pawn endgame, and the static, incremental updated score dominated by material is not outside a +-3 pawn window around zero: The extension is very powerful, it will often avoid REBEL entering a lost ending and vice versa.

See also

Publications

Forum Posts

External Links

References

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