noun
promotion/relegation playoff
Sports term for a match or series between teams facing promotion and relegation, typically between the bottom of a higher division and the top of a lower division.
Jリーグの入れ替え戦は毎年大きな注目を集める。
The J.League promotion/relegation playoffs attract a lot of attention every year.
入れ替え戦に勝ったチームが来季の1部昇格を決めた。
The team that won the playoff secured promotion to the first division for next season.