When Wizards tried to get into the Japanese market, they made a "beginner's" version of Magic The Gathering. It didn't take off, but the local (shell?) company decided to run with it, using local art and calling it "DuelMasters" and that took off like a rocket.
- no land cards. Instead, once on your turn you can play any card upside-down as land of the same colour
- no colourless cards like artifacts, because of the thing above
- simpler casting costs. You only need one mana to match the spell's colour, the rest of the casting cost can be any colour
- no power&toughness, all creatures have one number that is both (and always in the 1000s, Japan does that with all its card games I dunno why)
- creatures can't block attacks unless they have the "blocker" keyword
- no life points. Start the game by dealing the top five cards of your library face down in front of you as shields. If your opponent manages an attack for more than zero damage, you "lose" a shield and take one of those cards up into your hand. If you have no shields to pick up, you lose.
- no instants nor interrupts, you don't play cards from your hand on your opponent's turn... EXCEPT some cards have "shield trigger" keyword on them, and if you drew them into your hand because they're a broken shield you play them immediately instead.
It's faster, which means playing more games.