Kingdom Hearts X[chi] isn't exactly a proper KH game, but it does offer a card-battling formula somewhat similar to the one in Kingdom Hearts: Chain of Memories. This time around it's a browser-based game that has players tromping across Disney-themed worlds and fighting Heartless and "Lux" enemies with their decks.
Your personal avatar is customizable with different hair styles, gender options, and accessories, including Disney and Square Enix costume items. Simplified point and click controls move the characters around, bumping into enemies initiates card battles, and raid bosses that appear a few times each day will require players to work together toward victory.
If this sounds like a good time, AND you have a Yahoo! Japan ID, Square Enix is accepting applications for closed beta testers. Signing up nets beta players five ethers, five potions, 10,000 munny, and 2,000 card draw points. Here are a couple of the bonus support cards that come with a purchase of Kingdom Hearts HD 1.5 Remix in Japan.
Kingdom Hearts X[chi] is developed by Success Corporation (Operation Darkness, Metal Saga), and will be free to play when it arrives.