Type (designation)
The word "type" followed by a number or letter is a common way to name a device or product in a production series, similar in meaning to "mark". "Type" was used extensively by the Japanese and Chinese institutions beginning in the 1920s, and is still in use in both nations. The United Kingdom uses a type number system for much of their military equipment. Many other nations use the word "type" to designate products in a series.
Japan
The Imperial Japanese Navy and Army began using Type-Number Systems in the early 1920s, to designate armaments accepted for production, and Type-Letter Systems for classes of armament.The most common kanji character used to designate a "type" was, but it was also often translated to class to follow Western naming conventions. For instance, the destroyer Fubuki was described as a, but also a and a.
The "letter" system mostly added standardized kanji for clarification, usually translated as follows:,,,. For example, the destroyers were designated as "Type B destroyers".
The kanji character was often used to designate products in a series. The English language translation of shiki has been variously given as "model" or "type". Example, the. Some manuals and texts have translated shiki as both "model" and "type" within the same publication, confusing the matter. World War II-era military dictionaries do not give shiki as the Japanese word for "model"—instead, the kanji character kata is given. is also translated as "form", "type", "pattern", "mark", or "model".
The IJN began using the Type-Number System in 1921. For amaments, such as aircraft, naval guns, and other military equipment, the numbers used were based on the number of years that the Emperor Taishō had reigned. Since his reign began in 1912, an aircraft ordered into production in 1921 would have been called "Type 10", the tenth year of the emperor's reign. At the end of 1926, the emperor died, leaving his son Hirohito as the Emperor Shōwa, and the numbering system was reset to mark the new emperor's reign.
In 1929, the government of Japan adopted a new system based on the Japanese imperial year. Equipment ordered for production from 1929 onward were assigned the last two digits of the imperial year. Thus, an equipment ordered in 1929, aka the 2589th imperial year, would be designated "Type 89". As 1940 was the 2600th year, the IJN numbering system was reset to single digits, with equipment being designated 0 (zero) for that year. The well-known Mitsubishi A6M Zero was ordered into production in 1940 as the, and was popularly called the "Zero" because of its type.
In 1943, the designation system was abandoned by the IJN as it was considered too revealing about the nature of the armament. In its place, the armament were named with popular terms, such as for the Kawanishi N1K introduced in 1943.
The kanji was also often used to designate an improved type/version/model, eventually followed by an additional number when multiple remodels were introduced, closer to the "mark" system. For instance, the Kawanishi N1K1-J was known as the, with the later N1K2-J being the, and further remodels adding a number.
The IJA began using the Type designation system in 1927, for all weapons, vehicles, military equipment, subassemblies, and subsystems such as engines and gun mounts. In 1940, instead of resetting to zero, the IJA assigned "Type 100" to equipment put into production that year. In 1941, the IJA reset to "Type 1". Unlike the IJN, the IJA continued to use the system through 1945 with the production of the Kawasaki Ki-100 Army Type 5 Fighter.
Finally, some more unique pieces of hardware used custom designation, such as the various, or more descriptive types, such as the also known as the Sentaka-Dai type submarine.
After 1945, Japan's military changed to a numbering system based on the Japanese fiscal year, which begins on April 1 in the same manner as the British fiscal year. As an example, "Type 63" was the designation for equipment such as the Type 63 AT mine accepted in 1963.