Wooden tubs?
I’ve seen them mostly in movies but the Japanese have them all over the place. The Ofuro Bathtubs are these square wooden tubs that are designed mostly for soaking. In Japan they don’t use these for washing in and in fact they don’t often wash in a bathtub at all. They have an interesting custom to wash outside the bathtub and once their clean they get in the tub to relax. They often have maidens that pour water over you and you wash up then they rinse you off. The Wooden bathtubs used to be filled up permanently with water because they had to keep the wood swollen to maintain water proof.