The Hall of Fame format or Palace format (Japanese: 殿堂) is an officially-sanctioned format for Pokémon Trading Card Game events held exclusively in Japan. It allows cards released from the Diamond & Pearl expansion ownards, allowing a greater number of expansions than the Standard and Expanded format but not being as unpredictable in card combinations as the Unlimited format.
This format was created in March 2001 to create a more balanced gameplay experience. While it has a low number of banned cards, the Hall of Fame format has an additional restriction as the Star system (or Hall points). Certain cards have a set number of 1 to 4 stars, and the sum of stars in a player's deck cannot exceed four. For example, a deck may contain a 1-star and a 3-star card in its list, or four copies of a 1-star card but no other limited cards. If a card in a Hall of Fame-legal expansion is a reprint of an older card, all prints of the card can be played in an Hall of Fame-legal expansion-legal deck (e.g. Aquapolis Energy Switch). However, some cards significantly differ in wording between older prints and newer prints (e.g. Pokémon Fan Club from Aquapolis compared to its Ultra Prism iteration); those cards cannot be used in sanctioned tournaments. The exception is cards that have received errata (e.g. Base Set Potion); all printings of cards with errata may be used in sanctioned tournaments.
The Pokémon Company requires players to play with cards printed in their region's official language; therefore, only Japanese cards can be played in the format.
There were also a number of fan-curated formats, where cards had ratings between 1 and 8 stars for more granular rebalancing.[1]