I do not know Japanese at all, but I am reasonably confident that this won't be a huge obstacle, considering modern technology and US cultural dominance. I have not been to Japan in the last 30 years.
I've been solo traveling/roadtripping for just over half of 2025 (184 days, between late April and mid Dec). I am seriously considering traveling to Japan once I finish the 48 states. (related market: https://manifold.markets/JoeandSeth/roadtrip-will-i-complete-my-trip-an)

This market will resolve to the number of nights I spend in Japan in the calendar year 2026.
If I do not visit Japan in 2026, this market will resolve to the 0-6 bucket.
If I stay more than 90 days (due to gaining employment or requiring additional visa things) this market will resolve to the 61-90 bucket.

Related market: will I be in Japan on August 1, 2026? https://manifold.markets/JoeandSeth/roadtrip-where-will-i-end-up-in-one
Will I have a new job by August 1, 2026? https://manifold.markets/JoeandSeth/roadtrip-will-i-be-gainfully-employ

I will not bet in this market other than to bet NO in the 0-6 night bucket to encourage myself to take this potential travel more seriously.