diff --git a/src/search.cpp b/src/search.cpp index d6748c7696e..226506616c9 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -775,12 +775,9 @@ Value Search::Worker::search( // Step 7. Razoring (~1 Elo) // If eval is really low, check with qsearch if we can exceed alpha. If the // search suggests we cannot exceed alpha, return a speculative fail low. - if (eval < alpha - 469 - 307 * depth * depth) - { - value = qsearch(pos, ss, alpha - 1, alpha); - if (value < alpha && !is_decisive(value)) - return value; - } + // For PvNodes, we must have a guard against mates being returned. + if (!PvNode && eval < alpha - 469 - 307 * depth * depth) + return qsearch(pos, ss, alpha - 1, alpha); // Step 8. Futility pruning: child node (~40 Elo) // The depth condition is important for mate finding.