expression, ichidan verb
brace oneself; pull oneself together; tighten one's helmet strings
Idiomatic expression often used in the imperative form 勝って兜の緒を締めよ (after a victory, tighten the strings of your helmet) to mean staying vigilant and not letting one's guard down after success. The literal image is of securing one's helmet before battle.
See also: 勝って兜の緒を締めよ
After winning the match, I tightened my helmet strings and prepared for the next practice.
勝って兜の緒を締めよという言葉を胸に刻んでいる。
I keep in mind the saying 'After victory, tighten your helmet strings.'