The OP misses the fact that if you go anywhere in Japan right now and:

* order food

* shop in a store

* stay in a hotel

* consume healthcare (particularly old-age healthcare)

The likelihood that you're using immigrant labor is 100%. Japan is hugely dependent on immigrants -- particularly those from SE asian countries (e.g. Vietnam), who provide the bulk of the low-wage, low-skill labor.

Visit any hotel in Japan, for example, and the cleaning staff will be almost exclusively non-Japanese. Even the "traditional" inns in the smallest towns usually have "trainee" labor from foreign countries.