Outlet tubs

These tubs became common in the mid-Showa period (1950s and early 1960s) as in-house bathing grew popular in Japan; they were typically installed in relatively modern, well-kept wooden homes or in households with a bit of extra living space.
This particular model was known as the “Hon-futari” (literally “true two-person”) size.
It was the standard family-sized bathtub —designed so that two petite Japanese adults could sit side-by-side with their knees bent, or one adult and two children could fit in together.
This tub is significantly deeper than usual, allowing even a large person to fully submerge up to their shoulders.
On the other hand, if you are a regular or large body, it might be just perfect for a single user.