diff --git a/src/search.cpp b/src/search.cpp index 97ed196a..e2032638 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1469,6 +1469,18 @@ namespace { // Update transposition table TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_EXACT); + // Update killers only for good check moves + Move m = ss[ply].currentMove; + if (alpha >= beta && ok_to_history(pos, m)) // Only non capture moves are considered + { + // Wrong to update history when depth is <= 0 + + if (m != ss[ply].killer1) + { + ss[ply].killer2 = ss[ply].killer1; + ss[ply].killer1 = m; + } + } return bestValue; }