There is no known written evidence that can either confirm or deny that Musashi himself planned or endorsed this kind of behavior on the part of his students.
Did Musashi choose his duels well, being careful not to challenge the wrong swordsmen? If this was true then why did he accept a challenge from Kojiro Sasaki whom had created his own Ganryu sword fighting style? Both men practiced musha shugyo (austere training) and both had many well documented duels.
Deciding to look at another famous swordsman and contemporary, I had hoped to add some fresh perspective to this discussion.
I chose another Kenshi (sword saint) named Yagyu Munenori, one of the most prominent teachers of the day within a corresponding time period to be a contemporary of Musashi. Munenori was by all accounts an exemplary swordsman and teacher as well as a writer-philosopher of sword strategy. Because the Yagyu Shinkage Ryu (Yagyu’s New Shadow School) of swordsmanship prospered as the official line of swordsmanship for theTokugawa Bakufu (military government), Munenori’s activities are fairly well documented.
Like Musashi, Munenori was sought out by swordsmen and scholars alike to study heiho (strategies) and philosophy. In short, both men were known for their mastery of sword and brush.
Though most of what we think we know about Musashi emerged in accounts written well after his death and many of these accounts were self serving and more given to embellishment than fact , many of his writings in his hand survived. Musashi was a prolific writer/painter and left a body of brush writings and poems of the highest excellence. In short, Musashi like Yagyu is known and appreciated as much for his artistic genius as well as his skills with a sword.
So why didn’t Musashi and Yagyu ever cross swords? If the goal was to determine if a “superior” school of Kenjutsu (sword fighting) existed, why did this most obvious match-up fail to materialize?
From a historical perspective this comparison is very tantalizing because these 17th century kenshi (sword saints) had parallel lives in so many ways. Their actions and writings were common knowledge while they existed and before their names and deeds became legend and folklore. Invaluable for modern research and re-examination, these surviving writings require the discipline and knowledge of both the historian scholar and a technically proficient martial artist of Japanese swordsmanship to garner the deepest context possible. Obviously my own cursory comments and the abbreviated effort here will fall far short on both counts.
Both Yagyu and Musashi wrote extensively on sword strategy. Perhaps “Heiho-Kaden-Sho” is Yagyu’s most well known work. Musashi is known most for his work entitled “Gorin no Sho” (Book of Five Rings). Students of warfare, known as “heiho-ka” studied both works. Unlike Musashi, Yagyu was hired to promote The Tokugawa government’s policy to eliminate Japan’s incessant internal warfare and to prohibit brutal duels after the Senkoku(warring states) era. Towards this end, Yagyu’s writings were flowery, ambiguous, and considerably high class attracting the philosophers of swordsmanship. Musashi on the other hand was blunt, clear and practical, concise to the point of being Zen-like. His writings are likened to having been written from the reader’s perspective.
Munenori’s lofty heiho (philosophies on swordsmanship) explained that killing is wrong and a poor interpretation of the sword’s purpose unless by killing one evil it spares many innocent people, misery. This is the heart of his often quoted “Katsujinken”.  Munenori’s writings are replete with sayings such as: “One’s mind is similar to the moon in the water. Form will be the shadow of your own reflection as if it is on the mirror…” The reason for this metaphor is that water is to suggest the moon’s shadow and the mirror is to reflect your posture. The mind moves to a fixed thought as fast as the moon’s shadow is seen upon the water. The place where the sword rests is as water. If the mind is moved to the object then your body moves to the sword. The mind always obeys the body. This lovely and ambiguous declaration was and is considered “high class” prose within Japanese standards. It is unclear in the muddy waters of reality just how practical this advice was when a swordsman might find himself set upon by multiple assailants? The apex of this philosophy is “Mutou” (no sword is necessary). Simply by reading the maai (combative distance) and maintaining proper zanshin (concentration) the opponent would be discouraged. The perfect swordsman would never take his sword out first. By extension, reading distance effectively the perfect swordsman could sidestep an attack. One is perplexed however when thinking about environmental factors limiting movement or the opponent that draws a sword from afar and unable to discern the perfect technique and concentration of the perfect swordsman until too late.
The concepts of “Katsujin no Ken” (life giving sword) and “Satsujin no Ken” (killing sword) were romantic and inspiring, speaking to a more educated and refined class of warrior scholars. It was as elegant as it was spiritual and it is exactly how the Tokugawa wanted the Bushi or warrior class to behave. The Tokugawa nurtured this philosophical budo and did not promote the more combative systems that had emerged both in terms of access and financial reward.
One way that scholars support this argument is in studying the records of how much a master sword instructor might be paid. Yagyu Munenori for instance received a stipend of 160,000 koku of rice compared to Musashi’s 300 koku. Another famous sword school, the Onnoha Itto Ryu, famous for its practicality in terms of killing skills most famous sword saint, Onno Ittosai was paid 450 koku.
In the existing Tokugawa social order where everything was regulated why did some teachers prosper while others didn’t? Research would affirm that there was a conscious effort to control order and maintain peace by the ruling Tokugawa Shogunate by limiting and eventually suppressing these duelists. Government support was withdrawn from the propagation of multiple sword styles and multiple dojo (training halls).
As mentioned previously, the Yagyu Shinkage Ryu in Edo (Tokyo) was the anointed school of the Tokugawa Shogunate then in power. Discussing the philosophy of swordsmanship would have aspects that today might resemble a serious dojo bull session. When a question was asked about what action to take when found at the tactical disadvantage of being surrounded by multiple adversaries, we find very different kinds of responses from Munenori and Musashi to their deshii. Munenori’s elegant response was theoretical or spiritual discussing composure and bearing as well as the state of mental composure needed to overcome the problem. Musashi is practical, explaining body positioning, use of both swords and the need to group or bundle the adversaries together in order to improve the tactical situation.
There were also prohibitions against training and dueling with other styles of swordsmanship within the Yagyu tradition making it harder to test the qualities of the curriculum of the day. Munenori officially at least would’ve been prohibited from matching blades with Musashi.
It is likely to surmise that any defeat would hurt the reputations of these professional swordsmen as well. Prudence would not be a bad thing once a reputation was made. It is a refreshing exception to the typical declarations, of having never been defeated that the creation story of Muso and the development of Jojutsu (stick fighting) emerged out of a defeat at the hands of Musashi. (NOTE: See Muso & Musashi)
For those that argued that Musashi was a braggart there is his own art and writings to overcome and the question of whether he or his deshii reconstrued history to their own liking. He was a marketer. How else could he build a reputation and gain lifelong employment and security? As to the claim that Musashi chose his duels well, there is no evidence that he accepted all challenges or sought out every first class swordsman of the day. However it would be unfair to accuse him of avoiding Yagyu Munenori based upon the attitudes of the ruling Tokugawa and the rules within the Yagyu tradition that theTokugawa found attractive enjoining students from duels. It would also be a grandiose over-statement to say today that Musashi without doubt was the greatest swordsman than existed at the time.[i]
 See the article “Myths Die Hard” and the account about Kojiro, Sasaki.
 Much of what we know comes from an account of a surviving deshii (student) in “Nitenki”. Much of his XX X testimony however is impeachable because it does not match with other known facts. His writings reflect his overwhelming desire to elevate Musashi’s exploits at the expense of the facts more than to record them.
 Katsujinken is noted as proper in the dictionary. Yagyu Shinkage Ryu and Zen documents pronounces this term as“Katuninken”.
 A tradition based upon the philosophy of martial art could rest secure in the knowledge that the gun had replaced the sword as a true instrument of war.
 It is an interesting comparision: Musashi’s Nitto Ryu (2 sword school) vs. Onno’s Itto Ryu (1 sword school).
 The Nagoya branch of the Yagyu Shinkage Ryu today notates their origins as being the same as the Edo Yagyu. Munenoriwas the 5th lineal descendent. The departure (split?) happened in the time frame during Munenori’s grandson.
[i] In another article I will provide addition anecdotal evidence when overlaying the life of Muso Gunosuke the founder ofShindo Muso Ryu Jojutsu (stick fighting) to the extent that there is a nexus with Musashi.