Diagonal Mirroring

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Diagonal mirroring mirrors all pieces along the main diagonal or main anti-diagonal. It is applicable in pawn-less endgames with castling no longer possible. Along with horizontal and/or vertical flipping, diagonal mirroring is used in pawn-less endgame tablebases to restrict a white king to the 10 squares of the a1-d4-d1 triangle of the board.

=Sample Position=

=Mirroring an 8x8 Board= An 8x8 Board with a rank-file mapping needs to swap rank and file. A pure 8x8 Board may be mirrored along the main diagonal that way in C: int board[64], f, r, sm, sq, s;

for (f = 1; f < 8; ++f) for (r = 0; r < f; ++r) { sq = 8*r + f;  sm = 8*f + r;  s = board[sq]; board[sq] = board[sm]; board[sm] = s; }

=See also=
 * Color Flipping
 * Flipping, Mirroring and Rotating of Bitboards
 * Horizontal Mirroring
 * Vertical Flipping

=External Links=
 * Mirror from Wikipedia
 * Mirroring (psychology) from Wikipedia
 * Reflection (mathematics) from Wikipedia
 * Reflection (physics) from Wikipedia
 * Reflection symmetry from Wikipedia

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