Extra Battle Day, an event where you can enjoy Extra Regulation battles, will be held at Pokémon Card Gyms nationwide in Japan starting Saturday, January 23rd, 2021! All participants will receive the Shirona promo card as a participation prize! A rubber playmat with a special illustration will be given out as a prize for winning and as the rock-paper-scissors award! Players must purchase 6 or more packs of Pokémon Card Game products as a participation requirement. The event will be held at many Pokémon Card Gym locations, so come on out and join the fun!

Source: https://www.pokemon-card.com/info/2020/20201225_002733.html