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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


Ship Types

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.

Designator Definition Notes/Examples
AJ Army Transport Cruiser Legion Kagai-Class Assault Ship
AS Army Scout
NB Naval Battleship
NC Naval Carrier Kyoto
ND Naval Destroyer (escort)
NE Naval Escort (almost never used)
NF Naval Flagship (Command Battleships - eg Chiharu)
NG Naval Gunship Ender, Irim, Sakura, Plumeria, and Yuuko
NK Naval Star Fortress Iori, Zodiac
NJ Naval Junyokan (Japanese for Cruiser)
NL Naval Logistics (has the most ship classes)
NR Naval Repair Ship (used by some fleets for Anri DSRs)
NS Naval Scout Ship Yui, Nozomi

Fleet Types

Designator Definition Notes
L Logistics Star Army Logistics cargo and transport ships
S Standard Fleet Most fleets are standard fleets
TF Task Force Ships assigned to a task force that do not belong to a fleet
W War Fleet Huge fleets in the First Mishhuvurthyar War. Not currently used.
X Expeditionary Fleet Long-range exploration fleets

See also

stararmy/imperial_registry_number_irn.txt · Last modified: 2023/12/20 18:22 by