diff --git a/src/search.cpp b/src/search.cpp index 627a64af..fa483fbc 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -188,12 +188,6 @@ namespace { // Dynamic razoring margin based on depth inline Value razor_margin(Depth d) { return Value(0x200 + 0x10 * int(d)); } - // Step 8. Null move search with verification search - - // Null move margin. A null move search will not be done if the static - // evaluation of the position is more than NullMoveMargin below beta. - const Value NullMoveMargin = Value(0x200); - // Maximum depth for use of dynamic threat detection when null move fails low const Depth ThreatDepth = 5 * ONE_PLY; @@ -1094,14 +1088,11 @@ namespace { return refinedValue - futility_margin(depth, 0); // Step 8. Null move search with verification search (is omitted in PV nodes) - // When we jump directly to qsearch() we do a null move only if static value is - // at least beta. Otherwise we do a null move if static value is not more than - // NullMoveMargin under beta. if ( !PvNode && !ss->skipNullMove && depth > ONE_PLY && !isCheck - && refinedValue >= beta - (depth >= 4 * ONE_PLY ? NullMoveMargin : 0) + && refinedValue >= beta && !value_is_mate(beta) && pos.non_pawn_material(pos.side_to_move())) {