Hypothetical Trip to Japan - Do I have to buy a whole new Wii U? :O

[Pippin (Peregrin Took)]

So I've thought about in the past moving to Japan as a missionary/ESL teacher, and now the chance seems more real than ever before. If I wanted to become the next RetroGaijin (streamer on Twitch from Japan), would I have to buy a whole new Wii U or just a new power supply? I know both NA and Japan both run NTSC and all the controllers charge via USB or use AA batteries but curious about the system itself. I would like to not have to buy everything over again

 

[Moydow]

Region locking exists, so you'll need a Japanese Wii U to play Japanese games, and retain your current system to play games from your home country.
Japanese mains electricity is 100V, lower than Europe's 220/230V and the US' 110/120V, so you may need a step-up converter to use your current console (or use the power brick from a Japanese system, assuming the output/input ratings match up).

 

[Iceweasel]

Also worth mentioning is that even though the US and Japan both use the NTSC broadcast standard, that doesn't necessarily mean that they're compatible. The Wikipedia article is too technical for me to tell you why, but some older Japanese game consoles don't work on an American TV unless you change the channel to 95, iirc.

Of course, with the advent of digital televisions, this may no longer apply.