"The sword is known as the "soul of the Samurai", and in Japanese mythology it was one of the three sacred gifts given to the emperor by the Sun Goddess. A Samurai's sword was believed to be imbued with certain spiritual qualities of its owner. The forging of the blade itself was considered a religious ceremony, swathed in ritual, passed down in secret from father to son for generations. The ceremony was consistent, precise, unvaried, and beautiful -- in action, dress, and color. Forging was often done at night and temperatures were set by holding the blade to the color of the morning sun. The exact hue was transmitted from master to apprentice down through centuries.
The sword forging process itself became a metaphor for character development and many of the metallurgical processes parallel the tasks required for shaping the spirit. The concept of “tanren” is central to this theme.
Tanren means to forge in the same way that a sword blade is forged, with hard work, and sweat, and many hours of dedication, folding together the hard and soft elements in the body, mind, and movement just as the sword gains its strength out of hard and soft steel.
This is followed by “Renshu”. Ren means to polish, to perfect by continued practice. It also means to polish the spirit and character through the requirements of detail and interpretation. To demonstrate a compassionate nature that can pass on knowledge without egotistical pride and arrogance.
Miyamoto Musashi, the legendary 16th century Japanese sword master, states in his “Book of Five Rings” that it takes 1,000 days to forge the spirit and 10,000 to polish it."
By Yonjuhachi Ronin
Tai Chi Sword and Saber