It is known well that in the early Showa period there were contentions between two factions of army officers; the Imperial Way Faction (Kohdoh-ha) and the Control Faction (Tohsei-ha). Nagata Tetsuzan was a leading figure of the Control Faction and Mazaki Jinzaburo, the other. Nagata sent letters to Mazaki. This paper introduces five of them in Mazaki Collection owned by Modern Japanese Political History Materials Room in National Diet Library.