Idiomatic expression referring to a person's vulnerable spot, derived from the legendary warrior monk Benkei, whose shins were said to be his only weak point. The literal meaning 'Benkei's crying spot' is the shin, but it is used figuratively for any weakness.
彼は仕事は完璧だが、時間にルーズなのが弁慶の泣き所だ。
He is perfect at his job, but his laxness with time is his Achilles heel.
