かれをしりおのれをしればひゃくせんあやうからず

Japanese

For pronunciation and definitions of かれをしりおのれをしればひゃくせんあやうからず – see the following entry.
彼を知り己を知れば百戦殆からず
[phrase] (literal) know the other side and yourself, a hundred battles will not be perilous
[phrase] (figurative) it is important to understand the strength and weakness of your side and the opposing side, in order to mitigate the risk of failure
(This term, かれをしりおのれをしればひゃくせんあやうからず (kareoshirionoreoshirebahyakusen'ayaukarazu), is the hiragana spelling of the above term.)