multi-game competition; best-of-X series
Used in sports and games for a match decided over multiple rounds, such as a best-of-seven series. Often preceded by a number, e.g. 三番勝負 (best-of-three).
The Kisei title match is played as a best-of-seven series.
The final is a best-of-three match.
Compound of 番 (number, order) and 勝負 (match, contest). The exact historical derivation is uncertain, but it follows a common pattern for describing a series of matches.