You can buy courses for one platform (Web, Android, iOS) or make it available on all of them (Ultimate). If you purchase a course, you gain lifelong access to it. Subscription gives access to all listed courses on all available platforms for the duration of subscription period.
Get access to all Chess King courses on all platforms
You can enter a serial number from a recent Aquarium, Houdini Aquarium, Chess Assistant, or Chess King for your bonus subscription, or a promo code for a discount.
