An old woman finds a giant peach floating down a river, and a baby boy comes out of it, so he is named after it:
桃 "peach" plus
太郎, a classic name for an eldest son. Grown up, he sets off to fight the ogres of Onigashima, winning over a dog, a monkey and a pheasant with millet dumplings on the way. In Japanese he is Momotarō, and
冈山县 (Okayama) claims him as its own.
