This copy of Hoshi no Kirby will play on GameBoys of all regions in Japanese. Thankfully the game doesn’t require much reading at all to play.
From Wikipedia: Kirby’s Dream Land is an action platform video game developed by HAL Laboratory and published by Nintendo for the Game Boy. Released in 1992, it is the first video game in the Kirby series and the debut of Kirby. As the inaugural Kirby title it created many conventions that would appear in later games in the series. However, Kirby’s iconic copy ability would not appear until Kirby’s Adventure, released less than one year later.