Cool little set of servingware , agreeneyes .
Kinda doubt that they were made for sushi , as sushi is traditionally served in/on shallow , flat-ish dishes .
They'd very well work as sushi serving-ware , though , with sm bowls for wasabi , pickled ginger & etc .
They could certainly be rice bowls , or ones for serving side-dishes , such as daikon & etc . , with the smaller ones used for condiments/toppings like sesame seeds , bonito flakes & such .
Your little set looks like they were hand-formed on a die/pattern block & are hand painted .
From their gen'l 'look' I'd have to guess 1980's or so , maybe as old as 1970's , as far as I can tell .
Lets see what more members have to say