1 files changed, 21 insertions, 11 deletions
diff --git a/src/chess.h b/src/chess.h
index 2e9189a..305c681 100755
--- a/src/chess.h
+++ b/src/chess.h
@@ -716,19 +716,29 @@ typedef struct _POSITION
     // bbRookAttacks/bbQueenAttacks that will retire the rest of it.
     BITBOARD bbPawnAttacks[2];
 
-    // First mover of the bbMinorAttacks pair (knight only for now --
-    // bishop is a separate, later step; see board_representation/
-    // EVAL.md section 2). "Which squares does this side's knight(s)
-    // attack" -- computed via g_KnightAttacksBB[c] and OR'd in per
-    // knight, Eval()-scoped scratch like bbPawnAttacks above, cleared
-    // once per Eval() call in _ClearAttackTables since (unlike
-    // bbPawnAttacks) it's accumulated across multiple pieces via |=,
-    // not assigned wholesale. Bishop still writes its own minor-bit
-    // contribution into the old rgSquare[c|8].bvAttacks structure for
-    // now -- every consumer that needs "any minor's attack," not just
-    // knight's, ORs both sources together until bishop converts too.
+    // "Which squares does this side's knight(s) or bishop(s) attack" --
+    // knight ORs in g_KnightAttacksBB[c] directly (no per-square
+    // bit-scan needed); bishop ORs in _BishopAttacksBB(c,
+    // pos->bbOccupied), generate.c's magic-bitboard slider lookup.
+    // Eval()-scoped scratch like bbPawnAttacks above, cleared once per
+    // Eval() call in _ClearAttackTables since (unlike bbPawnAttacks)
+    // it's accumulated across multiple pieces via |=, not assigned
+    // wholesale. Rook/queen/king are not converted yet and still write
+    // their own bits into the old rgSquare[c|8].bvAttacks structure --
+    // see _IsSquareAttackedByMinor (eval.c), the transitional helper
+    // every consumer goes through until they convert too.
     BITBOARD bbMinorAttacks[2];
 
+    // Squares seen *through* a friendly bishop/queen battery partner
+    // or an x-rayable enemy rook/queen/king, for bishops only (knights
+    // never x-ray) -- see _EvalBishop's mobility loop. Same lifetime/
+    // clearing discipline as bbMinorAttacks above. Nothing else writes
+    // this yet (rook/queen have their own xray bits still living in
+    // the old bvAttacks structure), so unlike bbMinorAttacks' direct-
+    // bit case there's no old-structure fallback to combine with --
+    // see _IsSquareXrayedByMinor.
+    BITBOARD bbMinorXrayAttacks[2];
+
     ULONG uWhiteSqBishopCount[2];          // num bishops on white squares
     SCORE iMaterialBalance[2];             // material balance