- 知己知彼 zhījǐzhībǐ know your enemyknow yourself, know your enemy (idiom, from Sunzi's "The Art of War")
- 酒逢知己千杯少 jiǔféngzhījǐqiānbēishǎo drink with friendsa thousand cups of wine is not too much when best friends meet; used to express the joy of drinking and talking with close friends
- 知彼知己 zhībǐzhījǐ know both sidesto know the enemy and know oneself (idiom, from Sunzi's "The Art of War")
- 知己知彼,百战不殆 zhījǐzhībǐ, bǎizhànbùdài know your enemyknow yourself and know your enemy, and you will never be defeated
- 士为知己者死,女为悦己者容 shìwèizhījǐzhěsǐ, nǚwèiyuèjǐzhěróng reciprocal devotiona true gentleman will sacrifice his life for a friend who understands him, as a woman makes herself beautiful for her sweetheart
- 知彼知己,百战不殆 zhībǐzhījǐ, bǎizhànbùdài strategic awarenessknowing the enemy and yourself will get you unscathed through a hundred battles (idiom, from Sunzi's "The Art of War")
- 视为知己 shìwéizhījǐ regard as confidantTo consider someone as a close friend or soulmate; to take into one's confidence.
- 红颜知己 hóngyánzhījǐ confidantea close female friend who understands one deeply, often referring to a man's platonic but spiritually intimate female friend
- 蓝颜知己 lányánzhījǐ male confidanta woman's close platonic male friend or confidant
- 海内存知己,天涯若比邻 hǎinèicúnzhījǐ, tiānyáruòbǐlín spiritual proximitytrue friendship transcends physical distance; feeling close in spirit even when far apart