Structure: [breathing, alignment, triangle guard, posture, axis] [Okinawan Internal Arts - body mechanics (Rory Miller, Chiron Blog)]
Body mechanics often in Isshinryu referred to as "chinkuchi." Chinkuchi is limited when teaching such things as "body mechanics" or as Rory Miller coins from his post in reference to Kris Wilder, "Okinawan Internal Art or body mechanics for Karate." Taking it a step above the grade, it is actually those fundamental principles of all martial systems as posed by Stephen J. Pearlman in his book, "The Book of Martial Power."
I have posted many times on this; I have made many references to the fundamental principles as connected by the book; I have posted on Chinkuchi; I have given opinions on all of it and I find this new phrase of interest in regards to specifically Okinawan Karate. It is my theory that the fundamental principles of martial systems is more an intricate part of Okinawan karate practice then in other martial arts - I could and most assuredly incorrect in this assumption but what the hey, I like the phrase.
It appears to me that both phrases are interchangeable. Okinawan Internal Arts or Fundamental Principles of Martial Systems except that one has a wider encompassing feel and the other directs to Okinawan Toudi. You might consider that since the FPofMS is a wider net that the Okinawan Internal Arts can be system and culturally specific while encompassing all the FPofMS which has Chinkuchi or body mechanics as a part thereof.
Read Mr. Miller's entire post Sea Change. http://chirontraining.blogspot.com/2011/11/sea-change.html
Read Mokuren Dojo post "BOMP - Ch 27 - Structure." http://www.mokurendojo.com/2011/11/bomp-ch-27-structure.html
Final analysis findings: I find that both work well for what I would implement in teaching/instructing karate from Okinawa. I would fit chinkuchi into an overall Okinawan Internal Arts aspect as a part of the fundamentals (basics) as a lead in to the more involved FPofMS, fundamental principals of martial systems, as provided by the "Book of Martial Power" by Stephen J. Pearlman.