Alright, looking at my trusty "Infantry Weapons of WWII" book...
Arikasa's are right hand twist,
Taisho 6.5mm LMG, and Type 92 (7.7mm), 96 (6.5mm), and 99 (7.7mm) are all right hand twist.
The Japanese "Meiji 26" revolver in 9mm is left hand twist. It says that during WWII, they were carried primarily by reserve and home defence units, although many also made it into the hands of infantry units in the South Pacific. But, judgeing on the above description, this would be next to impossible.
From what I understand, the Japanese pressed captured arms into service (as did the Germans), so there are many other possibilities.