1. The bore diameter of Japanese Army weapons measures an even number of millimeters (metric system). However, the guns are designated by their nominal sizes, usually to the nearest even centimeter.

2. The bore diameter of Japanese Navy weapons quite often measures to an even inch in keeping with the English system, though some common Navy guns are designed with a bore diameter in an even number of millimeters. The Navy also designates its guns by no-minal sizes, usually to the nearest even centimeter.

3. To avoid confusion, ammunition is classified in this book by the nominal bore size of the weapon according to the Japanese nomenclature with the actual size given in pa-renthesis. In Navy ammunition above 5-cm. the actual size is given in both metric and English measurement.

4. Both services designate the size of guns under 5-cm by the actual size in millimeters, e.g. 47-mm, 40-mm, 30-mm, 20-mm.

1. Army Projectiles

The Japanese nomenclature for projectiles is followed as fas as practicable. The Japane-se Army terminology is self-explanatory and conforms fairly well with U.S. custom.

Needing some explanation are the therm A.P. and A.P.-H.E.

A.P. indicates a projectile intended for piercing heavy armor, for example, armor plate of thickness equal to or greater than the caliber of the projectile. These projectile have an H.E. bursting charge.

A.P.-H.E. indicates a solid-nosed projectile in general similar to the A.P. but designed for much lighter penetration. These carry an H.E. charge approaching that of a standard H.E. projectile. Hence, the term A.P.-H.E. is intended to indicate its intermediate status between an H.E. projectile and a heavy armorpiercing projectile. A.P.-H.E. projectiles are painted like H.E. projectiles but obviously they may be differentiated by their form.

2. Navy Projectiles

The classification and designation of Navy projectiles by the Japanese is highly irregular and cumbersone. Complete and accurate identification of a projectile requires identifica-tion of the gun, descriptive nomenclature of the projectile, and mark (or type) and modi-fication number.

14 cm/50
(Gun)

Ordinary
(General type of
projectile)

Type 0
(Design number)

For this reason an arbitrary system of nomenclature is used in this book. Japanese Navy nomenclature is given as a sub-title where known.

In Japanese Navy nomenclature all projectiles with a relatively high explosive charge (in-cluding light armor-piercing types) are designated TSUJODAN, which may be translated either "Ordinary Projectile" or "Common Projectile." Since this is a composite group includ-ing standard high explosive projectiles as well as light penetrating types, the translation "Ordinary" is used in this book for Japanese designations and the term "Common" is reser-ved for specific use as a descriptive title for light penetrating types of projectile (solid nose, base-fuzed) in accordance with the U.S. meaning of "Common". Projectiles having a point detonating fuze are designated "High Explosive" to conform with U.S. terminology.

W.P.

White Phosphorus.