Overview
Extra innings are additional frames played when the score is tied after nine innings. NPB caps extra innings at 12, declaring a draw if the tie persists, a rule unique to NPB with no MLB equivalent. This draw system carries strategic implications for pennant race standings. Bullpen depth becomes decisive in extra innings: clubs with thin relief corps are disadvantaged, and consecutive extra-inning games late in the season can trigger cascading fatigue effects across the pitching staff. As special measures during the COVID-19 years, NPB capped extra innings at the 10th in 2020 and played with no extra innings at all (nine-inning cutoffs) in 2021, before returning to the usual 12-inning format in 2022. MLB, for its part, introduced the tiebreaker rule (placing a runner on second base to start each extra inning) provisionally in 2020 and made it permanent in 2023. NPB has discussed tiebreaker adoption but as of August 2026 maintains the traditional 12-inning format.