Pokemon originally came out in Japan as Pokemon Red and Green, then later released in the US as Red and Blue.
This copy has been tested and works great, and has a new battery soldered in! The “NB” on the back of the cartridge is written in graphite and can be smudged off with a finger.
May look slightly different from the one in the photos. Will not look worse.
Japanese version works in any Game Boy from any region. Language is Japanese.