An extremely rare Pokemon card, thought to be one of only seven ever produced, is up for auction online and experts said it could sell for up to $100,000.

The Pokemon Super Secret Battle No. 1 Trainer card, being sold by Heritage Auctions, is billed by the auction house as the "holy grail" of collectible cards and its condition was rated a perfect 10 by experts at PSA Card.

The card is one of seven that were distributed to winners of regional tournaments in Japan in 1999, granting them entry into the finals in Tokyo.

"The Pokemon Card Game Official Tournament's champion is recognized here, and this honor is praised. By presenting this card, you may gain preferential entry into the Secret Super Battle," the card reads in Japanese.

Heritage Auctions said the card is "perhaps the most sought-after card, and arguably one of the rarest cards in the entire Pokemon Trading Card Game."

Experts said the card could sell for up to $100,000. The auction ends July 8.