Tamagotchi no Appare! Niji-Venture

'Tamagotchi no Appare! Niji-Venture' (たまごっちのアッパレ！にじべんちゃー) is a Tamagotchi game developed by Jupiter Corporation for the Nintendo DS. It was released only in Japan on March 29th, 2007. The third Tamagotchi entry for the DS, it's also a role-playing game, unlike the Corner Shop games.

*Gotchi King, the ruler of Tamagotchi Planet, has become so angry over the lack of rainbow in the sky that he cracked his shell. Princess Tamako tasks Mametchi, Memetchi, and Kuchipatchi to find the legendary "Rainbow Shards" to restore the rainbow in the sky before Gotchi King becomes too upset. The trio then travel around Tamagotchi Planet on their quest to find the shards while helping the Tamagotchis they meet along the way.

Take to the buzzing streets of Tamagotchi Planet with the original trio: Mametchi, Memetchi and Kuchipatchi, as you visit over seven memorable locations in hopes of seeking out the rainbow shards. With over 90 unique characters to inspect and socialize with, more and more clues will begin to uncloud... Appease the King's yearning for another rainbow, contribute to the community by assisting residents with their tasks and minigames, and try your very hardest to restore the colours in the sky; no matter how far-fetched it may sound!

(*Source of Description - Tamagotchi Fandom Wiki; 'Tamagotchi no Appare! Niji-Venture')