gubernatorial election; governor's race
Refers to an election for a prefectural governor in Japan. Often used in news contexts.
The gubernatorial election will be held next month.
彼は知事選に立候補する予定だ。
He plans to run in the governor's race.
Refers to the governor themselves, not the election.
Compound of 知事 (governor) and 選, an abbreviation of 選挙 (election).