Quote from the Gear Krieg background:
"Imperial Japanese Koumajutsu Platoon
Unit 100, originally created to research general biological warfare, was converted over to exclusive study and perfection of the zombie process. Chinese prisoners were first infected with the biological agents in what the Japanese termed the Koumajutsu, or demon invocation process. The drugs converted the victim into a cruel reflection of their former self. They became gnarled, aggressive and mentally stunted. There was no known cure for the biological agents used. Eventually, over the course of a few months, zombies would be consumed from within and die.
The Japanese would use their new discovery to horrifying effect. They used the process on thousands of Chinese and other mainland Asian peoples to create zombie fighting units. As hostilities with the Allies intensified, the Japanese started to use Allied POWs for zombie production as well. The effect was highly demoralizing, as Allied soldiers on patrol would be attacked out of the blue by mindless behemoths clad in the Allies' own uniforms!"
So see the above as Asian Zs under Japanese command...
Works, or?

OH and before you ask, USMC Zs are also being talked about already!