始めは処女の如く後は脱兎の如し

はじめはしょじょのごとくのちはだっとのごとしhajimehashojonogotokunochihadattonogotoshi

expression

1. hide your true strength, and then later swiftly attack the unprepared enemy
2. first be like a (meek) virgin, later like a running hare

Study it in Yanamino