Oblique Kick: MMA saves TMA

Normally we think of low kicks as leg kicks, or in other words round kicks to the usually-upper leg. This is swinging your shin like a base ball bat into your opponent's thigh, and it is probably the single most productive kick in the history of the martial arts:

However, this kick has a gory weakness, which is that a proper block of the kick does not completely protect the blocker, but is even more devastating to the kicker. In other words, its preferable to take a leg kick yourself than it is to have one of your leg kicks blocked properly. In extreme cases, a proper leg kick block has been known to break the leg of the kicker in two:

In traditional martial arts low side kicks and "oblique kicks" (stomps with the heel of the foot, with the toe of the foot pointing slightly to the direction of the side of the body from which it is thrown) are more common. The strange looking oblique kick is seen in all kinds of kung fu (every major type I can think of), Hapkido (which supposedly got them from Taekkyon, the ultimate "push kick" style,) some traditional Japeanese striking styles, very old Thai martial arts (even Lynn Thompson covers them in his instructional videos,) and many other martial arts. Starting at around 7 minutes, 45 seconds this Choy Li Fut instructor shows the very common kung fu technique of practicing oblique kicks on a wooden dummy:

However, until very recently, oblique kicks were pretty much unheard of in sport fighting. Low side kicks and oblique kicks are normally illegal in kickboxing and other full contact martial arts. The the closest thing to an exception to this I have heard of is in Taekkyon (real traditional Korean martial arts) battles where Judo-like sweeps sometimes double as low kicks (almost like shin-kicking from the UK):

Then controversially Jon Jones brought these traditional low thrust kicks kicking and screaming back into MMA. Here he is with his coach, Greg Jackson, explaining their use:

But Jon Jones is a notoriously dirty fighter, so I wrote this street fighting off as an anomaly. But then I saw Holly Holm defeat the invincible Rhonda Rousey, using those oblique kicks to help keep Rousey in striking range:

Now Holm is one of the most qualified strikers to ever compete in MMA, and she is using those oblique kicks more than regular leg kicks? I could understand if it was just a short cut so that she didn't have to learn round kicks, but she has a kickboxing background in addition to a boxing background, and she KOed Rousey with a round kick to the head. So where did these oblique kicks come from?

What Jones and Holm have in common in is coach Greg Jackson. It turns out he got these kicks from studying traditional martial arts for self defense as a youth. They come from Kenpo. This is another example of why MMA is the best thing that ever happened to traditional martial arts; now we know how these moves are used, even though they probably weren't sparred with for generations.

Of course this isn't the first time Kenpo has been seen in MMA: