Ash's Pikachu (Sinnoh Cap) .

This event was distributed to players with a 3DS of US, EU or TW regions, via common serial code.
The code was accurately guessed to be PIKACHU20, hours before its reveal on official sites.

The same code can be used to redeem other variations of this Pikachu, provided your save file hasn't received one via wonder card.
The variations receivable follows a schedule.
 

Species   Pikachu (Sinnoh Cap)   Nickname   (default, save lang)   OT   Sacha   TID   060407   Distribution   Serial Code   Location   a lovely place   Dates   Oct 03 to Oct 09, 2017   PID   Cannot Be Shiny   Games   US & EU 3DS: SM

Lv. 9

Nature   Hardy   Ability   Static (1)   Item   None   Bundled Item   Pikashunium Z  Wishing

Moves   (ITALIC means Relearnable)   Thunderbolt   Quick Attack   Iron Tail   Volt Tackle

WC ID 627: 「Pikachu Casquette de Sinnoh」's receiving text

0x2C Thank you for playing Pokémon! Please pick up your gift from the deliveryman in any Pokémon Center.

Format Ver.1.0.5-3, Post Updated Date:20171003_1123