Imperial Registry Number (IRN)

Imperial Registry Numbers, also called Hull Numbers, are numerical designations used by the Star Army of Yamatai to identify particular starships, starbases, and, in some cases, small spacecraft such as shuttles. They allow a ship's role and fleet to be determined at a glance.

Typical hull marking with “hinomaru” for a gunship in the First Expeditionary Fleet.

In YE 27, the current IRN replaced an older IRN system that IRNs starting with G for Geshrin and later Y for Yamataian. The older IRN system was not fleet-specific and thus more difficult to avoid numerical overlap.

• [Type]-[Fleet]-[Number]
• Typically N*-S*-123 or N*-X*-123
• Two or three digit numbers are the norm. A one digit number is never used.
• Shuttles and small craft IRNs reflect their parent ship (See examples)
• The preferred font is Conthrax SB. See: Typography of the Star Army of Yamatai

• NG-X1-408 is Nekovalkyrja Gunship number 408 in the First Expeditionary Fleet
• NF-S1-01 is the first flagship of the First (Standard) Fleet.
• NG-X1-361-1 for the first shuttle of NG-X1-361

The “N” was originally for “Nekovalkyrja” but now stands for Naval. All fleet ships in the Star Army fleet ships have hull numbers starting with N, except for Legion fleet ships.

• Civilian Imperial Registry Number (IRN)