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During the Spring and Autumn period, Qu Boyu, a virtuous minister of the State of Wey, consistently observed court etiquette. When passing by Duke Ling of Wey's palace at night, he would dismount from his carriage and walk, as prescribed by court regulations. He never failed to adhere to palace etiquette just because it was nighttime and no one was watching.
Duke Ling of Wey highly valued him for this, often praising him in court for his 'dark room, no deception' integrity.