The Navy system of marking projectiles for all sizes over 40-mm is relatively simple and reasonably consistent. Some discrepancies exist between the standard system and reco-vered specimens.

The following system applies to projectiles of over 40-mm, but carries over in part into the marking of smaller-caliber ammunition.

Body color: The main color of the projectile body indicates the basic type of shell.

* Japanese classification "ordinary" includes Common and capped Common projectiles as well as various designs of H.E. projectiles.

Color of nose: Certain additional information is indicated by the painting of the nose of the projectile as follows:

1. Green Nose. – Indicates "explosive filled". Specific identity of explosive is not made. Black Powder as well as H.E. is marked in this way.

2. Red Tip on Green Nose. – Indicates "base-fuzed", but is not used when ammunition is of the fixed type.

3. Yellow Nose. – Indicates "practice use." This is applied to standard practice projec-tiles, painted black, and may also be used to indicate projectiles converted form service types. Projectiles converted for practice retain their original painting except for the yel-low nose.

The length of the green or yellow tip is 100 mm for 12-cm gun and larger, 50 mm for 10- and 8-cm guns, 15 mm for 6-cm and smaller.

The length of the red tip is exactly half that of the green.

Center of gravity: The center of gravity of larger projectiles is indicated by a color band painted at the appropriate position near the middle of the body. The color of this band is varied to contrast with the color of the projectile body.

The center of gravity is not required to be marked on projectiles of 15-cm and under, but where projectiles of these sizes already bear the color band at the point of balance (ap-parently from earlier requirements) repainting is not required.

1. A black band painted on the lower edge of a projectile cap indicates a design of cap designated "type 3-year cap".

2. Fuzes and rotating bands normally are not painted. The bourrelet is consistently pain-ted.

3. The portion of the body between the rotating band and the base is left unpainted in projectiles of fixed ammunition, but is painted on projectiles of semi-fixed ammunition.

4. Dummy plugs resembling fuzes have the tips painted with black lacquer to distinguish them from fuzes.

Accessory markings: Type numbers or other characters are sometimes stenciled on the ogival portion of the projectile as a further aid in identification. Some of these markings are:

"91" indicating type 91 projectile design.

"88" indicating type 88 projectile design.

"Mk 5" indicating Mk 5 projectile design.

"Modifaction 1" referring to projectile design, but not a complete identifi-cation.

"Incendiary shrapnel."

"B" (rare) indicating a variation in explosive charge – presumably type "B" explosive.

"For practice use."

"For use with special reduced charge."

Filling data: On Navy projectiles of the larger sizes (8-cm and above), the dates of ma-nufacture and filling are painted or stencilled around the body of the projectile just above the rotating band, and again on the base of the projectile.

This markings usually consists of the following data in sequence as given (beginning at the right of the widest space and reading around the projectile to the right).

"Lot" followed by an entry like #72, M24, or 787 indicating the lot of explosive as manufactured.

"Manufactured" with a date like 17-3 (shows 17th year, 3d month or March 1942).

"Cast" followed by a date as above, to indicate the date the pre-formed block of explosive was cast.

"Assembled" followed by a date, indicating the date the block was installed in the projectile. This entry is some-times omitted or in-corporated into the Arsenal identification.

Rotating band marking: Certain information pertaining to the manufacture of the pro-jectile body itself is stamped into the rotating band. A typical example follows:

"Modification One" applies to the projectile design but is not a complete designa-tion. This sometimes appears as " ."

5/16 indicates 5th mounth, 16th year Showa (May 1941), the date of manufacture of the projectile body.

Symbol of the place of manufature, in this case Kure. The form of the an-chor varies with each factory. The place name or its abbreviation (e.g. Kure: or Sa for Sasebo) may also be included.

18.500 is the weight of the empty projectile body in kilograms. This may also be written 18 K 500.

Paper labels: Typically, but not without exception, there are two paper labels appearing externally on Navy ammunition, an oval one giving projectile data, and a square one giv-ing propellant data. Both carry valuable information on the ammunition components, and may be read at least partially with-out knowledge of Japanese.

In fixed ammunition both labels appear on the projectile. In semi-fixed ammunition, the oval label appears on the projectile and the square propellant label is glued to the metal disc in the top of the propellant case. In both types, the propellant label is duplicated by a cloth label sewed to the bag enclosing the powder sticks.

Projectile data label:

Propellant label:

Occaisonally the designation of the gun is included on the cloth label which is sewed to the propellant bag or may appear on a separate small label sewed near the propellant label.

"40 cal. 12.7 High-Angle Gun"

"Short 5-cm Gun"

Bursting charge label: The bursting charge for most Navy projectiles is cast in a paper container and inserted in the projectile as a separate unit and is held in place by pa-raffin.

Figure 345 – Markings of Japanese Navy Projectiles.