Japan had experimented with semi-automatic rifles in the 1930s, when the Imperial Japanese Navy tested rifles based on the Czechoslovakia
ZH-29. They were cancelled in the end due to problems encountered during testing. During the
Second World War, Japanese soldiers relied on bolt-action type rifles. However, guns were getting scarce and their main military opponent, the United States, had replaced their bolt weapons with modern semi-automatic rifles. At the same time,
Nazi Germany and the
Soviet Union were also developing their own semi-automatic weapons, such as the Russian
SVT-40 and German
Gewehr 43, which would give them a great advantage on the battlefield. Even
Italy used its own semi-automatic weapon, the
Armaguerra Mod. 39 rifle. This pressured Japan to find a quick way to cope with their military disadvantage. Instead of designing and investing in a new weapon from scratch, they opted to copy the American
M1 Garand. Initially, the Japanese experimented with re-chambering captured American M1 rifles, since the 7.7×58mm Arisaka Japanese cartridge has similar dimensions to the
.30-06 Springfield cartridge. Japan had previously developed semi-automatic service rifles, such as the
Type Hei,
Type Kō and Type Otsu but none of them had been viewed as successful or of trustworthy quality. The design work for the Type 4 rifle began in 1944. According to Japanese researchers, the official designation for the rifle is Type 4. However, the rifle is often incorrectly referred to as the Type 5, possibly based on an erroneous American technical intelligence report published in 1946. The Type 4 rifle was meant to be mass-produced in 1945. were completed out of the 250 in the workshop. Twenty of them were taken by the
Allies at the
Yokosuka Naval Arsenal on
Honshu after the end of the war. Examples of this rifle can be found at the
National Firearms Museum in
Fairfax County, Virginia, and the
Royal Armouries in
Leeds, United Kingdom. ==Variants==