管鲍之交

Explanation: Spring and Autumn Period, Qi Guan Zhong and Baoshuya know each other the most. After the often close relationship friend analogy. 　　Usage: Partial official; as object; with a compliment 　　Source: Qian Han, "Historical Records Guan Zhong Chuan": "a parent with me, I know who Bao Son also." Thesaurus:  friends in days of simple living, Year-end parties companion in adversity, sworn brothers and sisters companion in adversity, Absolute sincerity Centre at, close and intimate friend-ship, Stone pay