From the article: "The first portable game in the Kingdom Hearts series, Chain of Memories on the GameBoy Advance, took what everyone loved about Kingdom Hearts and turned it into a game with a card-based battle system. The game itself takes place between the two main PS2 Kingdom Hearts games. The second of the portable Kingdom Hearts games, 358/2 Days, has been released on the Nintendo DS. This game also takes place between the two PS2 games, and it even somewhat crosses over with the Chain of Memories storyline. Thankfully, they ditched the cards, and decided to go with the more traditional Kingdom Hearts combat."