Unfortunately only players from Japan can use Japanese cards. However, depending on where you are from, you are allowed to use foreign cards as long as they considered local.
15.8. Foreign Cards The use of foreign‐language cards have been known to create time delays and confusion at high‐ level Premier Events, where significant prizes are on the line. However, as the Pokémon TCG is an international game, concessions must be made to help accommodate markets where multiple languages are more common. Players are restricted on which language cards they can use, based on the country where they are playing. The list of countries and regions below defines which languages are considered local and which are considered foreign in that country or region.
Canada Local—English and French Foreign— German, Italian, Japanese, and Spanish
Europe Local—English, French, German, Italian, and Spanish Foreign – Japanese
Mexico and South America Local—English and Spanish Foreign—French, German, Italian, and Japanese
United States and Asia Pacific Local—English Foreign—French, German, Italian, Japanese, and Spanish
Players are permitted to use a limited amount of foreign cards at Premier Events. At a Premier Event, a player’s deck cannot contain more than 10% foreign cards (i.e., 6 foreign cards for a 60‐ card Constructed event). All of the cards in the player’s deck must have been released, in English, in the United States and must be legal for use according to the tournament’s format restrictions. If a player is using a foreign‐language card at an event, the player must have an English or local‐language version of the card, outside of his or her deck, for reference.
