Pawn Rams (Bitboards)

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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. Rammed none lever pawns in the center or extended center are most important to decide about bad bishops.

=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

=See also=
 * Backward Pawn
 * Blockade
 * Blockage Detection

=Forum Posts=
 * Pawn ram code in gnuchess by Chua Kong Sian, gnu.chess, June 18, 1994 » GNU Chess
 * Two ideas for pawn patches by Stephane Nicolet, FishCooking, July 28, 2016 » Stockfish

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

=References= Up one Level