I asked at check-in for my overnight stay.
You can bathe 24 hours except during maintenance, so they said that for heavy tattoos it's fine as long as you're considerate. There's also a private bath for 2,500 yen per 50 minutes extra, so I recommend that if you're worried. The two private baths are side by side, kind of a lukewarm one and a hot one.
I asked at check-in for my overnight stay. You can bathe 24 hours except during maintenance, so they said that for heavy tattoos it's fine as long as you're considerate. There's also a private bath for 2,500 yen per 50 minutes extra, so I recommend that if you're worried. The two private baths are side by side, kind of a lukewarm one and a hot one.
Totally OK! It was a great bath.