The same bosom, that is, compatriots, brothers and sisters. Xu Zhi's Epitaph of Yin Si Yuan Gong (Great-grandson of Yuan Keli) in the Qing Dynasty: "Four brothers in a family. A filial friend, Xianke Jue's family, the least uncle. " "Mr. Lu Xun has a famous saying:" It is enough to have a bosom friend in life, and the world should treat each other with the same heart. "It means that it is enough for a person to get a confidant in this life, and he should be treated like a compatriot born to his mother in this life.