Hiyashi Tororo Soba is cold soba noodles served in a bowl, with a bowl on the side that has in it puréed Yamaimo (aka Japanese Mountain Yam), and a raw egg.
You pour the puréed yam into the noodles and stir it all up to eat it.
You pour the puréed yam into the noodles and stir it all up to eat it.