Where do you find information regarding a rifle that was taken in World War 2 from a Japanese soldier?

Answer 1

The standard Japanese rifle of WWII was the Arisaka Type 38. It was a "38" because it entered production in the 38th year of the Emperor Meiji's Reign, in 1905 by the western calendar. This was a 6.5 X 50 MM weapon (roughly .25 caliber) a very small projectile in comparison to the standard shoulder arm of most other nations. It was a bolt action rifle of the Mauser pattern. There were several different variations. The rifles were produced at several different arsenals. The ones I have seen have no serial numbers, but do bear markings indicating the year of manufacture and the arsenal which produced it.

Because the light 6.5 X 50MM cartridge was unsatisfactory the Japanese began introducing the Type 99 Arisaka in 1939. The plan was to convert completely to the Type 99 but due to the war this was never possible. The Type 99 was very similar to the Type 38 but was a 7.7MM rifle.

Here's an article with some info:

http://findarticles.com/p/articles/mi_m0BQY/is_5_50/ai_114283920/

There are also Wikipedia articles with illustrations of some of the different types - look under "Arisaka".