The main difference is: Zhixin refers to being in tune with each other and knowing what each other is thinking, which is generally used between lovers; Zhiji refers to deep and close friends who understand each other; Zhiyin refers to like-minded people. Can appreciate each other, this is generally used between friends.

1. Intimate knowledge

From: Tang Dynasty. Li Jiayou. A poem to bid farewell to the Dukes of Piling

Original text: From now on we will say goodbye to each other, and remember each other’s hair spots on the temples.

Interpretation: Knowing that my heart will say goodbye, I will remember the person with gray hair on the temples.

2. Confidant

From: "Du Shaofu's Appointment in Shuzhou" by Wang Bo of the Tang Dynasty

Original text: There are close friends in the sea, and the world is as close as a neighbor.

Interpretation: As long as I have you within the four seas, I will be my best friend, no matter how far apart we are, we will all want to be together.

3. Zhiyin

From: Three Kingdoms. Wei. Cao Pi. Written with Wu Zhishu

Original text: When Xi Boya cut off his string at the Zhong period, Zhongni buried the grave in Zilu. He was deeply aware of the difficulty of finding music and could not catch anyone who hurt his disciples.

Interpretation: In the past, when Boya died in Zhongqi, Confucius and Zilu poured out the meat sauce, lamenting that it was difficult to find a close friend and that the injured student was not there.

Extended information

Synonyms

Zhijiao means friends who know each other.

From: Yuan. Jin Renjie. Chasing Han Xin. First Fold

Original text: You say we are brothers and we are friends, and we are friends. Oh, let’s be close friends.

Interpretation: If you become brothers and become friends, you will have many friends. Hey, let’s be friends.

Zhiyou means a close friend.

From: Han Feizi. Five beetles.

Original text: A person who knows his friends is insulted and follows his enemies is chastity.

Interpretation: When a close friend is insulted, a person who seeks revenge will be chaste.

Shenzhenjiao means deep friendship.

From: The Scholars. Chapter fourteen.

Original text: If you are a close friend of him, if you just watch something happen to him and cannot cover it up for him, then you are no longer a friend.

Interpretation: If you have a close friendship with someone else, if you just see something wrong with him and cannot cover it up for him, then you are no longer a friend.