Today is the very first day where you can download an Ash-hat Pikachu into your Sun and Moon game.
From today until the 25th, the Kanto-Johto hat worn by Ash in the anime is available.
If you want the OG hat, like me, you'll want to get this Pikachu. If you're waiting for another hat, return in a few weeks or so. The schedule is on the Pokémon website. ✌️
Credit to artist: kusatypelover on Twitter