What is Hapkido
Hapkido is a Korean art of self-defense, an offshoot of Japanese Jujitsu and cousin to Aikido. It emphasizes circular movement, redirection, and joint-locks, but it's a complete system that also contains kicks, strikes, throws, and grappling. If you're interested in its origin story, Wikipedia is your best bet.
Hapkido has techniques that can be found in several other arts including Judo, Taekwondo, and Jujitsu, but unlike those styles Hapkido has never been translated into a sport. This makes sense when you consider that it's premised on receiving and redirecting the force of your opponent—a concept that's simply incompatible with squaring off with someone in the ring. That's not to say we don't practice intensely, but there is nonetheless sparring and no tournaments in Hapkido.
Hapkido is for everyone regardless of size, age, or physical limitations from either previous injury or life in general. This is the way it's designed to be. Good technique is about leverage and positioning, not strength. Traditionally this is communicated through three principles called hwa, won, and yu. It gets a little philosophical, but the gist is that in Hapkido you never meet your opponent head on. Instead if you flow and adapt, you'll find that he does most of the work for you.