The story is called “Ji Zha hanging up his sword” in Chinese. It took place during the Spring and Autumn Period. Ji Zha was a nobleman of the State of Wu and the younger brother of the King of Wu. He was very intelligent and possessed high moral character.
Once Ji Zha was sent on a diplomatic mission to various states. When he arrived in the State of Xu, the King of Xu greatly admired Ji Zha’s sword. Although the King did not directly express his desire for the sword, Ji Zha understood his intention. Ji Zha needed the sword because he had a mission to a more powerful state, but he made a decision in his mind to present it to the King of Xu after completing his mission.
Later, Ji Zha continued his diplomatic missions to other states. When he returned to the State of Xu after completing his mission, the King of Xu had already passed away, therefore Ji Zha hung up his sword at the King’s tomb. His assistant could not understand, “But the king is already dead!”. To which Ji Zha replied, “I’ve made the promise in my mind, I can not break the promise because he’s passed away.”
From Records of the Grand Historian – Genealogies: House of Wu Taibo
#1 季札挂剑
季札挂剑的故事发生在春秋时期。季札是吴国的贵族，也是吴王的弟弟。他非常聪明，有很高的道德修养。
有一天，季札奉命出使各国。当他来到徐国时，徐国国君非常欣赏季札的佩剑。虽然徐国国君没有直接表达想要这把剑，但季札已经看出了他的心思。季札因为有出使上国的任务，还需要这把剑，但是他心里决定在完成任务后把宝剑献给徐国国君。
后来，季札继续出使别的国家。等他完成任务再到徐国时，徐国国君已经去世了。于是，季札在徐国国君的墓前挂上了他的佩剑。随从问，“国君都死了，为什么还要留下剑呢？” 季札回答，”当初我在心里已经答应给他了，不能因为他去世就违背自己的承诺。“
– 出自《史记 吴太伯世家》