The following are some of the basic principles that we teach to our student's in relation to Kyusho (point) utilization, these are also used to identify the factors/conditions that create those situations that allow for their use (and are also used to demonstrate/validate/discredit any principles/methods or techniques presently being taught or experimented with). We make every attempt possible to identify (for the student) the physical/neurological reasons for the demonstrated responses to the applied techniques. (Note* A Pain response/reaction is not considered “acceptable” to be the sole, or only factor for determining a technique's effectiveness). Very often, body motion/reaction (in response to the point's utilization) is the desired result from a point's use.
Muscle belly vs Muscle Tendon (and/or conditions that would affect either)
Directional Muscle Strikes (in-line vs cross)
Muscle “Fold” Strikes (between the muscles) when/where/direction of.
These “rules/principles” are usually shown in relationship to the individual techniques being taught/shown to a student at the time. Again, this aspect is not (overly) dwelt upon (during instruction).
Each of these are subjects which Taika has mentioned while demonstrating/teaching application of techniques. (Again) All that we have done, is to collect those concepts, and have provided a “list” (of them) for our student's use. Whether they choose to utilize them (or not), is their choice.
The knowledge of it's (Kyusho's) use, and/or effects, though definitely(in our opinion) “useful”, are not mandatory knowledge for a technique's effective application, nor for a student's continuing study. Though versions of many of the provided concepts are utilized by numerous methodology's/systems, student's are not always (made aware of ?) familiar with their relationship to a technique's application. In addition, though many of these are demonstrated/explained singularly, they most often are utilized in conjunction with each other (i.e. “multiple” principles are being utilized during a technique's application).
It's my opinion, that this is sufficient (and more than enough) information to explain the majority of what "we" teach (in regards to basic kyusho implementation). Exact targeting and direction (of strikes) is often dependent upon the required result and/or situation (as opposed to simply knowing "where" to strike). That aspect, should be studied/discovered from individual research (meaning "figure it out for yourself", LOL). All of the above theories, can be found (in/on medical related sites) on the internet. They aren't (personally) created or made-up theories, they are established principles that are presently utilized by various medical practices. We are (only) applying them in relation to what we are doing.