Since around the Sengoku period (period of warring states) (Japan), a custom in which samurai used a name without his government post as his own name occurred among the samurai class, and continued by the end of the Edo period.
戦国時代(日本)の頃から、武士の間で官名を略したものを自分の名前として名乗る風習が生まれ、江戸時代後期までその風習が続いた。