It's time for some Japanese wordplay! Oshawott's Japanese name is Mijumaru (ミジュマル), and the kanji for Mie (三重県, mie-ken), can also be read as "Mijuu". As such, Oshawott is very important to Mie Prefecture. Since December 2021, it's been the prefecture's Support Pokémon as part of the Pokémon Local Acts program, which seeks to support tourism to different localities across Japan.
The date March 10th, specifically the numbers 3/10, can read mijumaru (ミジュマル) in Japanese goroawase, or number wordplay, which makes use of how numbers can have several different readings/pronouncations in Japanese.
- Mi (ミ) has the same pronouciation as a kun'yomi reading of 三 (Mi), meaning 3.
- Ju (ジュ) has the same pronounciation as an on-yomi reading of 十 (Juu), meaning 10, except it cuts off the second syllable, so the wordplay here is to have it represent just 1.
- Maru (マル) is pronounced the same as Maru (丸), meaning circle, or 0.
- Sources
Mie×Oshawott|Pokémon Local Acts
Event highlights, goods, artistic utility hole covers and other features related to collaborative projects designed to promote Japan’s localities involving “Ambassadorial Pokémon,” whose characteristics match those of their respective localities.local.pokemon.jp