Pins

[cdani]

Maybe give a penalty if a piece is undefended in middle game. But that may also be too costly.

You know what I will say

For example in Stockfish:

Code: Select all

// Enemies not defended by a pawn and under our attack
    weak =   pos.pieces(Them)
          & ~ei.attackedBy[Them][PAWN]
          &  ei.attackedBy[Us][ALL_PIECES];

Fast and relative easy with bitboards

[Henk]

Maybe give a penalty if a piece is undefended in middle game. But that may also be too costly.

You know what I will say

For example in Stockfish:

Code: Select all

// Enemies not defended by a pawn and under our attack
    weak =   pos.pieces(Them)
          & ~ei.attackedBy[Them][PAWN]
          &  ei.attackedBy[Us][ALL_PIECES];

Fast and relative easy with bitboards

I only use bugboards.

[Henk]

There are even more pins for instance after d3d4 knight can not move for white will play b5b6. So there are pieces that shield weak squares like square c7.

Maybe give a penalty to each weak square. But it might be difficult or expensive to detect weak squares.

[d] 1k1r1bnr/1pp1p3/5pp1/pPN1n2p/2P2B2/3P4/P3BPPP/1R1R2K1 w - - 0 22