Sparring with a partner who is a pretty accomplished striker I have come across a new kick. A good striker can often see a roundkick to the legs or body coming fairly well and step back just out of range for the kick to whiff. Whiffing with a properly executed round kick results in turning a full 360 and exposing yourself to a counter. Bas did this a lot in his pancrase fights, jumping back just enough for the kick to whiff and counter with a kick to the legs... So taking that into consideration you can bring the leg up and around just like you are throwing a roundkick to the body, but at the point your leg stretches out completely with the foot turned sideways piston your hip out a bit and into the target. The heel plows into the target, and you can aim for the solar plexus or the spleen/liver. I practiced this kick against my partner and he said it comes out looking identical to a roundkick, but hits more like a front kick without being so telegraphed. you can really plow into someone with this kick with a lot of power, and unlike the bullshit TKD or Karate style sidekick you really don't run the risk of having the kick jammed by the oponent moving into it cuz if he does you simply catch him with a round kick. Plus now I can actually somewhat adjust a roundkick to land with the heel-plow effect if they back away from the range of my round-kicks... especially if I throw a few roundkicks and he backs away from them, and then I throw one of these. Try it out and give me some feedback. Wish I could make a video of it.