I'm updating my prior post, as some folks asked me about the acronyms.
BJJ - Brazilian Jiu-Jitsu. A Judo-derived style (via Mitsuyo Maeda) emphasizing ground grappling. Pioneered by the Gracie family. (Arguably influenced by CACC, though given the paucity of lower-body locks prior to John Danaher's contributions, this seems apocryphal.) Ground-level combat is emphasized in HKD to the extent that we'd like to get vertical as quickly as possible if dropped in a self-defense situation. We're sport to learn new tricks, but our aim really isn't to roll with BJJ assassins.
CACC - Catch-as-catch-can wrestling. A submission grappling style epitomized by Farmer Burns, Frank Gotch, Billy Robinson, Yoshiaki Fujiwara, etc. It boasts a rich repertoire of super-nasty "hooks" that work great for finishing a thrown opponent in HKD.
HKD - Hapkido. The way of coordinated power. A hybrid Korean style whose schools operate in a loosely coordinated, federated manner, consistent with the "water principle" (i.e., that polymorphism and adaptability to differing circumstances are desirable). Other basic principles include non-resistance to force (redirect/ leverage it instead) and circular motion (many techniques have a spherical aspect). I find the philosophical consonance of HKD with Bruce Lee's Jeet Kune Do remarkable, though perhaps unsurprising given Lee's connection with the renown Hapkidoist, Dojunim Ji Han-Jae?
JJJ - Japanese Jujutsu. Jigoro Kano carved out a subset of JJJ, "nerfed" it (theoretically!) for competition among school-age youth, and in the process introduced the Olympic sport of Judo. Judokas will immediately recognize certain takedowns, joint locks and chokes used in HKD. Some of the more painful HKD locks probably originate from daito-ryu aiki-jujutsu, a JJJ lineage from which Morihei Ueshiba's Aikido was derived. (On the basis of a perfunctory reading of the Westbrook-Ratti text and some online video surfing, I fail to see terribly much correlation between Aikido and HKD, despite certain claims to the contrary.)
TKD - Taekwondo. The foot fist way, an Olympic sport, and a beautiful fusion/ evolution of Taekkyeon, Gichin Funakoshi's Shotokan Karate, Tang Soo Do, etc. Aside from extrinsic weapons, TKD's kicking techniques provide the longest-range attacks used in HKD. A substantial difference is, similar to Kyokushin Karate and Muay Thai, HKD encourages strikes to the legs. Similarly, HKD's fist fighting comes more from a Western Boxing angle than from the hand strikes used by TKD.
To re-emphasize my earlier point, I thoroughly enjoy training in GM Kim's Hapkido formulation, which impresses me as a modern-day Pankration of sorts. HKD is akin to the Borg in Star Trek, continuously assimilating what's useful and jettisoning the residual. I've recently begun cross training in TKD with GM Kim (World Taekwondo/ Kukkiwon provides an interesting counterpoint to the Tang Soo Do-like Chung Do Kwan/ ITF variant I grew up with) and this has really helped to clean up my striking skills in HKD and get my aerobic capacity back to something respectable. read more