Kawa no Nushi Tsuri 4 is a Game Boy Color fishing game released in Japan. Part of a series (indicated by "4"), it most likely features various fishing locations, different types of fish to catch, and possibly upgrades or customization options for fishing gear.  The gameplay would revolve around the act of fishing using varied techniques.  Information on the publisher and specifics of the game's features and storyline would require delving into Japanese-language sources.

Kawa no Nushi Tsuri 4 (Japan)

Karate Joe (Europe) (Unl)