There is simple game to win one Pika Ball everyday.|
Hit on 'Explore' on the main land, and new screen will open showing 4 balls. You should discover which one is real Pika Ball. to do this, you can follow easiest way by checking all balls, while there is no check limit, you will find the correct Pika balls.
Mostly, you have to check all 4 balls, first 3 will be wrong, and the final choice will be the correct.