Analysis:

A short story written by Ryunosuke Akutagawa, Japan, whose original Japanese name is "River Boy", refers to an amphibian in Japanese folklore. It has a tiger-like face and scales, and is shaped like a four-or five-year-old child. The author bet on the original question: Please read kappa. Or kappa can be considered a river boy.

Bajie in Travel Notes is a river boy.