Hankido and Hapkido
The difference between hapkido and hankido is that hankido is much more an internal art where hapkido is a semi-internal art. Hankido emphasizes the use of three principles, which are Won (圓), Yu (流), and Hwa (和), and using the power of softness.
To give the hankido practitioner more insight into these principles, there are three exercises they can practice, the Sam Dae Wolly (삼대원리). The name of the exercise representing the circle-principle is called Jeon Hwan Bub (전환법). The name for the exercise of the flow-principle is called Young Nyu Bub (역류법) and the last exercise, representing the heart-principle, is called Shim Hwa Bub (심화법). This last one is also referred to as the rowing exercise.
Read more about this topic: Hankido