Maruyaso

A small family-run minshuku in Funatsu, built around one indoor bath, split for men and women, that guests can soak in any time of day or night. The water comes from the Shurei-no-yu (秀麗の湯) source, one of five that opened Fujikawaguchiko's onsen district back in 1997, and the bath has jets built in. Day-use bathing is accepted as well, even though the official site doesn't mention it. The building itself is old, with steep stairs and no elevator, but that's part of its charm: an elderly couple runs the place with real warmth, meals and futons go out on tatami, and several rooms look straight out at Mount Fuji and Lake Kawaguchi.