かれをしりおのれをしれば、ひゃくせんあやうからず

彼 を 知 り 己 を 知 れば 、 百 戦 殆 からず

  1. expressions (phrases, clauses, etc.)

    if you know your enemy and know yourself, in a hundred battles you will never be defeated, know your enemy
    from Sun Tzu's The Art of War
    proverb