九きゅう仞じんの功こうを一いっ簣きに虧かく

expression, godan verb (-ku)

to fail one step short of great success; to fall at the last hurdle

A classical Chinese idiom (故事成語) used to describe a situation where a great undertaking fails just before completion due to a small final mistake or lack of effort. Highly literary and rarely used in everyday conversation.

• 九きゅう仞じんの功こうを一いっ簣きにかくとは、最さい後ごの一いっ歩ぽで失しっ敗ぱいすることだ。

  九仞の功を一簣にかく means failing at the final step.