Why do the characters on the brims of old Japanese navy sailors' hats differ?

This thing is called the front seal of a sailor's cap. Before the Seventeenth Year of Showa (1942), the Japanese Navy's cap had its own deployment written on it. The XX ship was written on the XX ship, and the artillery technical school was on the artillery technology. School.

In addition, IJN recruits had to go to the Marine Corps for training before boarding the ship. At that time, Japan mainly had Yokosuka, Maizuru, Kurejin, Sasebo and other military ports, and then these recruits had to receive Marine Corps training here. Their hat banners say "XX Marine Corps" or something like that.

On October 30, 1942, the Japanese Navy was afraid that ship information would be leaked through the navy caps, so they uniformly changed the front seal of the sailor caps to Imperial Japanese Navy