​The purpose of this article is to ask whether the definition of the word 'sadae' in the dictionary is right. Dictionary says 'sadae' means a small country worships a strong and big country. I think it is too modern-oriented interpretation. According to my study, 'sadae' was a method of foreign policy to keep their kingdom from other stronger kingdoms in the Middle Age. But from the late 19th century, 'sadae' became to have some negative meaning which we have today. I researched the change of meaning of 'sadae' through the writing of that time.​