A complete first edition run of the Base Set from the 1999 release of the Pokémon Trading Card Game recently fetched six figures, selling for $107,010 at Goldin Auctions. The complete run contained all 103 cards in the set, all of which were graded PSA Gem Mint 10.

For some of the cards in the Base Set, there are less than 50 accounted for in this grade.

“For many Millennials, the original 1999 Pokémon video/card games remain a staple of their childhood, providing what seems like a lost art in a nostalgic feeling. With kids a like trading cards at the lunch table, or virtually via Gameboy’s connect cable, it was apparent from the beginning that Pokémon is not only special, but part of a generation. For a generation such as the Millennials it signals the end of the tangible toy age and the beginning of the virtual age as no other item became as popular or as connective as Pokémon in years following,” Goldin Auctions’ description of the set reads. “Even more impressive is the fact that Pokémon remains popular today and just like Star Wars, is arguably more popular than ever with kids and adults taking part in the different games that the vast World of Pokémon offers. Some argue that it will become as important to modern collecting as the 1986-1987 Fleer basketball set or the 1909-11 T206 White Border insert set.”

Pokémon cards have seen high prices before, though its clear that the Base Set and other early sets are on the rise; an unopened booster box from the Base Set sold last year for $56,000 through Huggins & Scott.

The Pokémon Trading Card Game is a collectible card game developed and published by Media Factory in Japan, and first by Wizards of the Coast in the U.S. before The Pokémon Company took over in 2003. The game has players taking on the role of a Pokémon Trainer, using the titular creatures to battle their opponent. The goal is to “knock out” the opponent’s Pokémon by dealing enough damage; once a Pokémon has been knocked out, the player can select a Prize Card. The primary win condition is for a player to take all of their Prize Cards before their opponent can do the same.

As of this article’s publication, there have been 84 different Pokémon card sets released in English. The first of these was the Base Set, which had a few different print runs. Cards are available as either First Edition Shadowless, Shadowless, or Unlimited, with Shadowless being called as such due to how the Pokemon portrait on the card did not feature the drop-shadow effect that later became the standard. First Edition Shadowless and Shadowless cards featured smaller print runs and therefore see higher prices at auction when compared to their Unlimited counterparts. Certain cards, such as Charizard in particular, tend to demand high prices on their own simply due to the popularity of the Pokémon itself.

More information about the history of the Pokémon Trading Card Game can be found in The Overstreet Guide to Collecting Tabletop Games.