[forgotoldacc]

Not sure where you're getting "secretly" from since there was no secret and they were openly obedient to Japan. There's nothing outside of CCP sources, and particularly no historical sources, that could even remotely claim otherwise.

And even if you goalpost shift to the Meiji Restoration, 1872 is still well before any period where Japan was required to give up any territory as a result of WW2 imperialism.