Daido Juku is a hybrid martial art or mixed martial art that has its main roots in Kyokushin karate and judo, with influences from many other popular styles in MMA like Muay Thai and Brazilian jiu-jitsu.

(For those of you who don't know what Kyokushin is, it ain't your daddy's karate. Kyokushin practitioners are rather well-known for sparring and fighting bareknuckle, although they do also train with gloves when punching to the face.)

Daido Juku competitions are different from typical MMA matches in that fighters wear Kyokushin gis, MMA-type gloves, and foam helmets. The gis allow for a range of judo throws that are generally more difficult to perform when fighting no-gi. The helmets are not meant to prevent head trauma, but rather to prevent cuts and broken noses from elbows and headbutts. (Headbutts are banned in regular MMA competitions, and elbows tend to stop fights early due to cuts that won't close but that aren't disabling to the fighter.)

Perhaps the largest criticism of Daido Juku might be that ground-and-pound in the style hasn't developed as it has in regular MMA due to restrictions in the Daido Juku ruleset that limits striking on the ground. Still, as you can see from this highlight video, these guys are serious business.