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		Pawn Rams, all pawns that are blocked by the opponent's pawns. A ram is a mutual mechanical obstruction. If the rammed pawn is no lever pawn, it becomes member of the immobile pawns. Specially if other properties match, e.g. there is no or no mutual lever-possibility against the opponent counterpart, rams are a symptom of congealment. The term Ram or Widder in German (Ovis, Aries) was coined by Hans Kmoch [1] [2]. Rammed none lever pawns in the center or extended center are most important to decide about bad bishops.
Samuel Bak - Locked [3]

Blocked Positions

Three or four isolated rams are a perfect barrier - no path for either king to enter to opposite area.

. . . . . . . .
. . . . . . . .
. . . . . . . .
. b . . b . . b
. w . . w . . w
. . . . . . . .
. . . . . . . .
. . . . . . . .

Code

Working in the bitboard centric world to determine pawn related pattern set-wise.
The code snippets rely on shifting bitboards, specially by one step only.

U64 wRam(U64 wpawns, U64 bpawns) {return soutOne(bpawns) & wpawns;}
U64 bRam(U64 wpawns, U64 bpawns) {return nortOne(wpawns) & bpawns;}

Obviously the number of white rammed pawns is equal to the number of black rammed pawns.

Mutual Mechanical Obstruction

Mutual Mechanical Obstruction [4]

See also

• Backward Pawn
• Blockade
• Blockage Detection

Forum Posts

• Pawn ram code in gnuchess by Chua Kong Sian, gnu.chess, June 18, 1994

External Links

• Pawn Power in Chess by Hans Kmoch - Glossary of Terms - Chess Forums - Chess.com
• Monsoon/Typhoon Homepage by Scott Gasch

References

1. ^ Hans Kmoch (1959, 1990). Pawn Power in Chess. New York: Dover, 1990. Previous ed.: New York: McKay, 1959. ISBN 0-486-26486-6
2. ^ Pawn Power in Chess by Hans Kmoch - Glossary of Terms - Chess Forums - Chess.com
3. ^ Chess in the Art of Samuel Bak, Center for Holocaust & Genocide Studies, University of Minnesota
4. ^ Kämpfende Steinböcke ... fighting ibex from Flickr - Fotosharing!, kleinwegen.net

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