Not sure why this particularly struck me as different from what I would expect back home – could just have been a made up cultural difference to save me from taking a bath, as I’m a shower man myself…
The first thing is that in Japan someone does really need to get in the bath with the baby, because the bath tub is too deep and the sides are too high to make putting baby in the bath and holding him/ her from outside practical. As I said a couple of posts below, it is traditional for dads to bathe first when the water is cleanest, so it would make sense for baby to go in then too. I also have a feeling it gets Dad out of the way so housework can be done and is a sign that it is assumed he can’t do anything more useful around the house!