Experience is obtained by playing either ranked or practice matches. You will receive experience regardless of a win or loss. Your current experience is shown by the purple star icon on the main screen. Unlike rating, experience does not decrease.
Experience is used to unlock the ranked mode. Once you reach 5000 experience by playing practice matches, you will be able to play ranked for rating.
Experience in the Shop Edit
You may unlock direct buying or selling of different ranks of pieces with either your rating or experience. You may also unlock the ability to purchase upgraded units by gaining enough experience.