The bakugan game is played with two types of cards. There are gate cards which are the thick ones that the bakugan pop open on and there are the ability cards which are the thinner regular cards that are played during the game to affect gameplay.In a normal game each player needs 3 gate cards as well as 3 ability cards to play (in addition to 3 bakugan). The gate cards and the abilty cards are color coded (some older cards are not) and to play you need one of each of the three colors. Gate cards come in gold, silver and bronze/copper. Ability cards come in red, blue and green. In the short time that bakugan has been out, they have come out with a few different card sets. There is a 1-15a set, a 1-48 set, 1-48b set, 1-48c set, 1-48d set, 1-48e set, 1-8f set, 1-48i set,1-4m set and 1-48n set. In addition there is an older set that isn't numbered this way and you will see an "hsp" value in the bottom corner. The 'hsp" value was used in the past to determine a winner but the rules have since changed. These cards can still be used but the "hsp" value is just ignored. There also have been a few promo cards that have been released.The 1-48 set came out with Series 2. The "b" set came out when the bakupearl series came out. I also believe the "c" set came out with the bakuclear set and the "d" set came out with the bakuswap set. The "e" set came out with the Bakuneon set. The "i" card set came out with the BakuBronze series. The "f" set came with Bakugan Traps and Special Attacks. The "n" set comes with the ?? series. The "m" set came with the newest Bakugan Traps and Special Attacks. The "hsp" cards came out with series 1. Anyone wants to share some ideas,tips about the bakugan cards. Please feel free to post.