// Step 8. Futility pruning: child node (~50 Elo)
if ( !PvNode
- && depth < 6
+ && depth < 8
&& eval - futility_margin(depth, improving) >= beta
&& eval < VALUE_KNOWN_WIN) // Do not return unproven wins
return eval;
continue;
// Futility pruning: parent node (~5 Elo)
- if ( lmrDepth < 6
+ if ( lmrDepth < 8
&& !ss->inCheck
&& ss->staticEval + 284 + 188 * lmrDepth <= alpha
&& (*contHist[0])[movedPiece][to_sq(move)]
if (type_of(move) == CASTLING)
extension = 1;
+ // Late irreversible move extension
+ if ( move == ttMove
+ && pos.rule50_count() > 80
+ && (captureOrPromotion || type_of(movedPiece) == PAWN))
+ extension = 2;
+
// Add extension to new depth
newDepth += extension;