diff --git a/src/search.cpp b/src/search.cpp index d654fec9..e0252932 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1314,7 +1314,13 @@ namespace { ss[ply].currentMove = MOVE_NULL; pos.do_null_move(st); - int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction + + // Null move dynamic reduction based on depth + int R = (depth >= 5 * OnePly ? 4 : 3); + + // Null move dynamic reduction based on value + if (approximateEval - beta > PawnValueMidgame) + R++; nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);