When you're doing this kick, what part of the foot do you prefer to hit with, the blade of the foot or the heel and why?
I'll post my answers shortly!
Mike
For some reason found myself going through some of my foundational books referencing some basic technique or other, and happened to remember this thread/question. And since my view differed from most (often use side of foot vs. heel), thought I'd see if the stuff I rely on for back-to-basics proved me wrong. Here's what I found (now granted, this is limited to my library, so pretty small sample--but some names are recognizable).
My first serious book on technique from way back when was Bong Soo Han's,
Hapkido: Korean art of self-defense. He says/illustrates striking edge of the knife foot (Chok-Do) is the 'outside edge or the blade of the foot'. He shows the heel of the foot as used only for a straight on thrust kick (Deet-Bahl-Deum-Chi).
Kung Fu Basics by Paul Eng has been a short, sweet handbook for me. His section called 'Side Kick' says specifically that the outside edge of the foot is used as a knife edge, and as such is one of the strongest kicks in the kung fu arsenal, potentially stronger than the heel thrust (which, as Bong Soo Han, he shows only as a straight-on kick).
Bruce Tegner's complete book of self-defense recommends as one option the 'edge-of-shoe snap kick', mostly to the shin, although he also recommends the 'Stamp kick', which appears sometimes to be a side thrust, or side kick using the heel.
Major W.E. Fairbairn in
Get Tough! shows the Boot (Side Kick), very much like Tegner's (actually, Fairbairn obviously preceded Tegner). He also identifies the 'Boot Defense', which is scraping the side of one's boot down the enemy's shin from top to bottom.
Simon Harrison in
Kung Fu for girls: Self-defense with style, recommends using the edge of the sole of the shoe 'for scraping bones', much as Fairbairn's Boot Defense.
Another book I use for reference is
Kung fu elements: Wushu training and martial arts application manual. Now, as the name says, this is Wushu and a lot of it is obviously meant for acrobatic more than combative application. Still, I notice that one of the kicks discussed is called the Low Cut Kick (xiachuaitui), with the outside edge of the foot at a downward angle (so, practical for mid-thigh down on a standing opponent).
Anyway, if nothing else proved to myself that the writings of at least some people whom I consider pretty knowledgeable stress the side of foot as a blade kick. :ultracool