Yamanochaya
山の茶屋
You can use the bath with your tattoos visible. Nothing to cover, no size limit, and nothing to declare at the desk.
No restrictions. The ryokan answers the question directly in its own FAQ: tattooed guests may use the daiyokujo. Four communal baths — three open-air, one indoor — plus a reservable private bath in the valley.
タトゥー、刺青を入れてますが大浴場に入れますか？ はい、ご利用頂けます。
The operator’s own wording, copied from the page linked below. Holding up your phone settles the question faster than explaining it.
There is nothing to do. Check in, go to the bath. No seal to buy, no measuring, no declaration to make, and no size at which it stops being allowed. If a member of staff does query it, the operator’s own wording is above — showing it ends the conversation without either of you needing the other’s language.
Confirmed Confirmed from official site (FAQ answers the question directly)
Read on: yamanochaya.com/faq/
Best for: A valley ryokan at Tonosawa that says yes in writing, in its own FAQ
One of the few places in Hakone that addresses tattoos on its own site rather than leaving it to directories. The private bath in the valley is bookable separately, 15:00–24:00, 45 minutes.
Hakone is a resort onsen town, where the rule has historically been firmest. What works here is mostly private bathing; a listing that takes tattoos in a shared bath is the exception rather than the pattern.