Move ordering is the process of sorting moves so the most promising ones are searched first, which dramatically improves alpha-beta pruning efficiency. Stockfish uses information such as: best moves from previous iterations, captures sorted by SEE (Static Exchange Evaluation), killer moves, counter-moves, history heuristics, and NNUE suggestions. Good ordering ensures early cutoffs, saving huge amounts of computation because inferior moves are pruned quickly. In practice, strong move ordering is the single biggest multiplier of search speed—good ordering makes pruning powerful; poor ordering makes it weak.