To become a ninja, you must first of all start off by receiving your very first cards, the shiny you get will either be a 10 fire or a 10 water or a 10 ice. There is no best, they are all equally good. The aim of the game is to use your cards which sensei gave you, or maybe some you unlocked by code, and to use them against your opponent. Water beats fire, fire beats ice, ice beats water. If for example you used a water then he/she uses an ice, then they win that round.
To win a match, you need to have either 3 different symbols in different colours or have the same symbols 3 times in different colours, there the only ways you can win.
The aim of card jitsu is to earn all the belts and beat sensei, if you do that, he wll give you the ninja mask and access to the ninja hideout
Thanks for Reading, and goodbye!