3 Treatises on Swordsmanship - and Zen...

The Battle of Sekigahara on October 21, 1600 cleared the path to the Shogunate for Tokugawa Ieyasu. Though it would take three more years for Ieyasu to consolidate his position of power over the Toyotomi clan and the daimyo, this battle is considered to be the unofficial beginning of the Edo period, or Tokugawa shogunate.

At the beginning of this period, 3 short treatises on swordsmanship appeared which would become influential far beyond what their authors originally intended.

The First classical treatise on swordsmanship was The Mysterious Record of Unmoving Wisdom, (Fudochi Shinmyoroku) written by Zen Master Takuan Soho around 1632. This treatise looks at Swordsmanship from the perspective of Zen. 
It specially emphasizes the importance of keeping the mind free of attachment and fixations.  
On the battlefield, this means keeping the mind from stopping on anything, whether the stance, the opponent's sword, the technique, anything that could prevent the mind from moving freely.

The Second classical treatise on swordsmanship was The Life Giving Sword (Heiho Kandensho) written by Yagyu Munenori around 1632 also. The philosophy of this treatise is based on the above mentioned Fudochi Shinmyoroku written by Takuan for his friend and disciple Munenori.

It emphasizes in a similar way the importance of keeping the mind free of attachment to details of techniques, or even to the idea of winning. This treatise is however much more technical in its description of certain techniques Munenori inherited from his father and his father's master, the legendary Kamiizumi Ise no Kami Hidetsuna.

The Third classical treatise was the famed Book of Five Rings (Gorin no Sho) written by Miyamoto Musashi between 1643 and 1645. Although the Philosophy underlying Musashi's book is also to keep the Mind Free from any attachment, Musashi puts high emphasis on the technique of Swordsmanship, and does not consider the willingness to win as a hindrance, but as a mean to complete one's duty to one's Lord, but the willingness to survive the fight as one attachment that could mean defeat. 

Yagyu Munenori was a disciple and friend of Takuan. It is not clear whether Musashi ever met Munenori, although they were together in Edo(Tokyo)in 1623. Musashi also very likely met Takuan around 1630 after he had been temporarily banished to Northern Japan.

Numerous translations of these treatises are available, but I particularly enjoy the ones by William Scott Wilson. 

These are :

The Unfettered Mind – includes the Fudochi Shinmyoroku and 2 other texts by Takuan.

The Life Giving Sword by Yagyu Munenori

The Book of Five Rings by Miyamoto Musashi.

Mr Wilson gives us clean, accurate and lively translations of these 3 great texts. Although he is not himself a swordsman, the help he received from persons qualified in this domain make his translations very valuable for whoever is interested in how Martial Arts and Zen were related in 17th century Japan.