For no particular reason other than I was bored and waiting for the weather to warm up slightly before attacking my backyard, I googled "Five Point Palm Exploding Heart Technique," and came up with this link.
Although it's over-done as is traditional in martial arts films, apparently there are such fatal points (use babelfish translating from Chinese) that can be hit in martial arts.
As one commenter on that blog noted, it has a lot to do with cultivating and directing the flow of 気(ki), or, as I just found out (what a dummy I am), this energy in Zen is called "jouriki," (that part I knew) which is represented as "定力" (and is pronounced "じょうりき") -that is, the "jo" part is lengthened slightly.
定力 is composed of 2 kanji/hantsu: "定" means "fixed," or determined, and "力" means "power" (as oppsed to "気" which means "energy.")
"力" is also pronounced as "chikara," or "ryouku" in other words.
So 定力 is simply then the power of being grounded when zazen is practiced.