The Japanese military did not have a Marine Corp. What they did have was a Naval Infantry Division of the Imperial Japanese Navy. The Special Landing Forces being the closest to the American Marine Corp.
On a side note. Japan was probably the wost off weapon wise of all of the axis combatants. Even though it has adopted the 7.7mm caliber before the out break of WWII, it had never fully trasitioned over. So that both 6.5mm and 7.7mm weapons were still in use through out the war. On top of the logistical problem. The Japanese had several different 7.7mm cartridges, they used a copy of the Lewis machine gun which was still chambered for the .303 British. In Metric nomenclature .303 is 7.7mm
Thank for the info about Japanese naval infantry.I guess the Axis power could not make up their mind about what caliber they wanted to go to war with because the Italian did the same thing when they tried to replaced the 6.5 mm with 7.35 mm .