Hitler envisioned a pure Empire with plenty of lebensraum for his master-race, but did the Japanese have any similar ideas? I've hear Hitler admired the Japanese for their supremacist views on their race, and they did treat the peoples they conquered, especially the Chinese, with wanton cruelty. Though, as far as I know the massacres perpetrated by the Japanese were a result of these supremacist views mixed with an army that treated its own soldiers with extreme cruelty and failed to supply them as well, forcing them to "forage" for supplies, but not stemming from a systematic goal to exterminate those it deemed inferior.
But did Japan have any plans for the vast swathes of land they conquered teeming with people they viewed as sub humans?
This is a subject of considerable dispute, as you might imagine.
Generally speaking, the Japanese Empire of the Pacific War era needs to be understood as being fully culturally and politically contiguous with earlier Meji-era Japanese economic and political ideologies. There was never the same clear change in political systems as German experienced during the 1920s and 1930s.
Despite their brutal treatment of the civilians in China and elsewhere in Asia, the Japanese leadership seems to have generally wanted to keep the native populations intact and economically productive, but under benevolent Japanese overlordship. Obviously, since Japan was the most sophisticated and advanced of the Asian nations, it was only right that Japanese culture be advanced as the dominant cultural medium. I think it's indicative that Germany called it's new imperial state "The Greater German Reich" while Japan called theirs the "Greater East-Asian Co-Prosperity Sphere". Japanese leaders seem to have wanted access to the resources of East and Southeast Asia without having to actually run the place outright -- that's part of why they set up puppet states like Manchuko.
On the other hand, Japan seems to have regarded Korea as a integral component of a future metropolian Japan. For all the propaganda of "ancient brotherhood" between Japan and Korea (with Japan as the wiser eldest brother, of course)and made considerable effort, largely unsuccessfully, to assimilate the Korans into Japanese culture encourage them to speak Japanese. This included forcing Koreans to take Japanese names, and forbidding the publication of newspapers and books in Korean.
For further reading, there was an excellent post about this a few months ago: https://www.reddit.com/r/AskHistorians/comments/2uu3qm/both_korea_and_formosa_taiwan_were_under_japanese/cobz6tt