主しゅになる

expression, godan verb (-ru)

take the lead; take the initiative; be the leader

Used when someone steps forward to lead a group or activity, often in a proactive or responsible manner.

• 彼かれが主しゅになってプロジェクトを進すすめた。

  He took the lead in advancing the project.

• 誰だれかが主しゅになって計けい画かくを立たてる必ひつ要ようがある。

  Someone needs to take the initiative and make a plan.