Tattoo access
Women (Japanese or foreign): trial admission for fashion tattoos. If any single tattoo exceeds 30 × 30 cm, one ¥330 facility sticker is required; if there are multiple tattoos, no sticker is needed when each is within 30 × 30 cm. Foreign male tourists: one sticker plus passport or airline-ticket proof. Japanese men and foreign male residents with tattoos are refused, even with a sticker.
The guide says a sticker may extend beyond the tattoo and still be acceptable. “Fashion tattoo” is not defined. The rules differ by sex and residency; confirm your eligibility with the facility before visiting.