@ryo @lolicon @roboneko @antisophon @x0x7 Bitejo has job listings that pay in Monero. Most of them aren't in Japan but you probably could work remotely, given your specialty.
https://bitejo.com/search/tasko/
Agorist.Market has a catalog of businesses that accept alternate currencies. Most of them are local and in the US though. If you do find a business accepting alternate currencies, tell them to get their business on there.
In the meantime, you can trade directly with your neighbors (things like produce or services like mowing lawns) using alternative currencies like precious metals or just simple bartering.