Sanchin no Kata literally means ‘Kata of three battles or conflicts’, from the characters San - 三 (‘three’) and Chin - 戦 (‘war’, ‘battle’ or ‘match’). no Kata - の型 means ‘Kata of …’. But the real meaning of Sanchin no Kata is interpreted as the battles of the Body, Mind and Spirit.
Sanchin no Kata is considered to be the oldest Kata and the most important Kata of Karate (along with Tensho). The true history of Sanchin no Kata has been lost to antiquity. But according to the Karate lineage, Kanryo Higaonna (Higashionna in Japanese; Naha-Te) brought Sanchin no Kata back to Okinawa from Southern China (Fujianese). His student Chojun Miyagi (founder of Goju-Ryu) made changes to Sanchin no Kata (open spear hands to closed fists, and changed the breathing to more direct and less circulatory in nature). This version Sanchin no Kata is still used in most styles of Karate, including Kyokushin.
Three elements are practiced with Sanchin no Kata. The Body component is the most apparent, it involves breath control, muscle tension and relaxation, grip, proper posture, proper Kamae and balance/stability. To conquer the Mind requires intense concentration, shime conditioning and visualisation, among others. The battle of the Spirit has to do with creating harmony between the physical and mental aspects of Sanchin no Kata. This is our will, or intention, to push our abilities to the highest level.
In practicing Sanchin no Kata we strive for Kime - 決め, the exact amount of power, focus and speed to make a technique effective. The right combination not only leads to the strengthening of the body, but also to the development of the inner power Ki - 気 ('vital energy') and the coordination of mind and body. Ki is located in our Nōten - 脳天 ('crown of our head'), the Hara - 腹 ('diaphragm') and our Tanden - 丹田 ('lower abdomen'). With Ibuki - 息吹 ('deep breathing'), by expanding our diaphragm and creating a spine perpendicular to the earth, we optimize the conditions for building good Ki and transferring the energy through our bodies. The cultivation of our spiritual energy is the basis of our entire practice both in and outside the Dojo. Sanchin no Kata can be classified as ‘moving Zen’, our way of meditating in Karate.
It is easy to see why Mas Oyama would want the Kata as part of his Kyokushin Karate. He considered the three most important principles of Kata training to be Waza no Kankyu - 技の緩 ('the tempo of technique'), Chikara no Kyojaku - 力の強弱 ('the points of power stress'), and Iki no Chosei - 息の調整 ('breath control'). Sanchin no Kata teaches all the three aspects, and as well, through it’s Shime - 締め testing, it would demonstrate The Ultimate Truth.
Sanchin no Kata made its way into the curriculum of Kyokushin Karate as a Southern Kata because of Sosai Oyama’s extensive background in Goju-ryu, under sensei Nei-Chu So, and his teacher, Gogen Yamaguchi. Mas Oyama trained from time to time with Gogen Yamaguchi, even joining the latter’s Goju-kai and obtaining the rank of 7th Dan Black Belt.