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Created page with "'''Home * Search * Selectivity * Extensions * Passed Pawn Extensions''' '''Passed Pawn Extensions''' are triggered after a Passed Pawn|passed pawn..."
'''[[Main Page|Home]] * [[Search]] * [[Selectivity]] * [[Extensions]] * Passed Pawn Extensions'''
'''Passed Pawn Extensions''' are triggered after a [[Passed Pawn|passed pawn]] is established on the seventh or sometimes sixth rank, that is after a [[Pawn Push|pawn push]] or [[Captures|captures]] with a [[Pawn|pawn]]. The idea is to avoid [[Horizon Effect|horizon effects]] regarding a possible [[Promotions|promotion]], and to determine whether the [[Stop Square|stop-]] or [[Promotion Square|promotion square]] is or may blocked, defended or supported. Clearly, this extension heavily interacts with the [[Evaluation|evaluation]] of passed pawns, and may also restricted to certain [[Node Types|node types]] and distance to horizon. Some programs also extend promotions itself and not only if there starts a threat to promote.
=Colin Frayn=
[[Colin Frayn]] on Pawn Push Extensions <ref>[http://www.frayn.net/beowulf/theory.html#extend Computer Chess Programming Theory - Search Extensions] by [[Colin Frayn]]</ref>:
# If a pawn is pushed to the 7th rank, or promoted, then extend.
# This helps spot winning tactics in the endgame.
# Not so useful if your endgame analysis function is good enough at handling passed pawns.
=Forum Posts=
* [https://www.stmintz.com/ccc/index.php?id=112415 Passed Pawn Extensions] by [[Roberto Waldteufel]], [[CCC]], May 24, 2000
* [https://www.stmintz.com/ccc/index.php?id=210570 passed pawn extension] by [[James Swafford]], [[CCC]], January 28, 2002
* [https://www.stmintz.com/ccc/index.php?id=252677 PASSED_PAWN_PUSH extension scheme (and SmarThink)] by [[Sergei Markoff|Sergei S. Markoff]], [[CCC]], September 18, 2002
* [http://www.talkchess.com/forum/viewtopic.php?t=56311 Adding an Extension Results in Deeper General Search!] by [[Steve Maughan]], [[CCC]], May 10, 2015
=External Links=
* [http://www.top-5000.nl/authors/rebel/chess840.htm#PAWN-EXT Extension Techniques in REBEL (pawn)] from [http://www.top-5000.nl/authors/rebel/chess840.htm Programmer Corner ] by [[Ed Schroder|Ed Schröder]] <ref>How Rebel Plays Chess is also available as [http://members.home.nl/matador/Inside%20Rebel.pdf pdf reprint]</ref>
* [http://www.frayn.net/beowulf/theory.html#extend Computer Chess Programming Theory - Search Extensions] by [[Colin Frayn]]
=References=
<references />
'''[[Extensions|Up one Level]]'''
'''Passed Pawn Extensions''' are triggered after a [[Passed Pawn|passed pawn]] is established on the seventh or sometimes sixth rank, that is after a [[Pawn Push|pawn push]] or [[Captures|captures]] with a [[Pawn|pawn]]. The idea is to avoid [[Horizon Effect|horizon effects]] regarding a possible [[Promotions|promotion]], and to determine whether the [[Stop Square|stop-]] or [[Promotion Square|promotion square]] is or may blocked, defended or supported. Clearly, this extension heavily interacts with the [[Evaluation|evaluation]] of passed pawns, and may also restricted to certain [[Node Types|node types]] and distance to horizon. Some programs also extend promotions itself and not only if there starts a threat to promote.
=Colin Frayn=
[[Colin Frayn]] on Pawn Push Extensions <ref>[http://www.frayn.net/beowulf/theory.html#extend Computer Chess Programming Theory - Search Extensions] by [[Colin Frayn]]</ref>:
# If a pawn is pushed to the 7th rank, or promoted, then extend.
# This helps spot winning tactics in the endgame.
# Not so useful if your endgame analysis function is good enough at handling passed pawns.
=Forum Posts=
* [https://www.stmintz.com/ccc/index.php?id=112415 Passed Pawn Extensions] by [[Roberto Waldteufel]], [[CCC]], May 24, 2000
* [https://www.stmintz.com/ccc/index.php?id=210570 passed pawn extension] by [[James Swafford]], [[CCC]], January 28, 2002
* [https://www.stmintz.com/ccc/index.php?id=252677 PASSED_PAWN_PUSH extension scheme (and SmarThink)] by [[Sergei Markoff|Sergei S. Markoff]], [[CCC]], September 18, 2002
* [http://www.talkchess.com/forum/viewtopic.php?t=56311 Adding an Extension Results in Deeper General Search!] by [[Steve Maughan]], [[CCC]], May 10, 2015
=External Links=
* [http://www.top-5000.nl/authors/rebel/chess840.htm#PAWN-EXT Extension Techniques in REBEL (pawn)] from [http://www.top-5000.nl/authors/rebel/chess840.htm Programmer Corner ] by [[Ed Schroder|Ed Schröder]] <ref>How Rebel Plays Chess is also available as [http://members.home.nl/matador/Inside%20Rebel.pdf pdf reprint]</ref>
* [http://www.frayn.net/beowulf/theory.html#extend Computer Chess Programming Theory - Search Extensions] by [[Colin Frayn]]
=References=
<references />
'''[[Extensions|Up one Level]]'''
