// Step 1. Initialize node (polling is omitted at root)
ss->currentMove = ss->bestMove = MOVE_NONE;
+ (ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE;
// Step 2. Check for aborted search (omitted at root)
// Step 3. Mate distance pruning (omitted at root)