Each teacher has his own ideas of what sanchin should eventually develop in a dedicated practitioner. With few exceptions, they are all valid ideas, again depending on individual interpretation.
I see Uechi as a formidable personal defense system against acts of random attacks on the person.
In such situations the 'defender' needs to make every 'contact' with an opponent count as a stopping technique because his chances at 'delivery' on target will be seriously limited in the chaos of the moment.
The question is...what training method/concept seems to develop the most effective stopping techniques...and does this particular practice include sanchin practice?
There are countless opinions on this...usually, if a student possesses this ability, is quickly revealed, to me personally, just by watching him perform Sanchin, Seisan, and Sanseiryu.
One article on this that I always enjoyed reading is this…
http://sirnica.livnoweb.com/fajin-in-uechi-ryu-karate/The Fajin correlation is of interest
Quote:
ELEMENTS OF FAJIN IN UECHI-RYU KARATE
By David Elkins, L.C.S.W
This article will examine two movements from the hojo undo (preparatory exercises) sequence of Uechi-Ryu Karate and explore elements of fajin (expressed energy) contained therein. Each hojo undo sequence will be described, andfajin implications will be presented.
The material of the kata from which hojo undo derives is profound yet its depths are only revealed to those who earnestly seek. Without such research the movements of kata, and hence a designated style, are at best limited in application. The importance of physically using the movements of kata–individually and in combination–to obtain understanding and ownership cannot be overemphasized.
The process of ingraining the movements of kata into the neuromuscular memory of the body is something akin to target shooting. Knowledge of ballistics without practice on the firing range produces no success. Therefore, it is the utilization of both mental and physical energies that allows one to master the movements of kata.
Only then can the practitioner begin to see kata not as a catalog of so many techniques but rather as an encyclopedia of energy vectors which are governed by concepts of structure and movement, thus having unlimited potential for bunkai.
It is unusual to associate concepts such as fajin with systems of karate. Understanding the history of Uechi-Ryu karate will make meaningful discussion of material usually associated with the study of Chinese gung-fu.
UECHI-RYU KARATE
Uechi-Ryu Karate is a system of civil combative concepts, techniques, and strategies initially taught by Kanbun Uechi Sensei (1877-1948), and later elaborated by his eldest son and successor, Kanei Uechi Sensei (1910-1991.) The nucleus of the Uechi-Ryu system was learned by Kanbun Uechi Sensei during the period of thirteen years that he lived, studied, and taught in China (1897-1910.)
Although scholars believe that Master Uechi studied at several kenpo (way of use of the fist) academies during that period, the majority of his instruction was from Nan Chuan (southern fist) Sifu, Chou Tzu-Ho. Chou Sifu was reputed to have expertise in several fighting styles notably, Tiger Boxing. The Uechi style was initially known as Pangainoon Ryu Karate-Jutsu and represented an amalgam of fighting concepts, techniques, and strategies of the Tiger, Dragon, and Crane Boxing systems.