There is a Yagyū tsuba (sword guard) designed by the 5th headmaster Yagyū Renya Toshikane. It is inscribed with four characters, “Ten, Chi, Jin and Marobashi” (heaven, earth, person and turning/changing). These characters represent the spirit of Yagyū Shinkage Ryū, namely sei shizen, shinjitsu no hito and marobashi.
Sei shizen is the principle of following natural movement. We should use the sword with our whole bodies in a relaxed manner, without attachment to our egos. This is expressed in the phrases unification of mind and body and unification of sword and body. This comes from the concept that if we were to follow natural movement, we would respond appropriately to everything around us. If we were to find our true selves, everything would be done appropriately. This is Shinmyōken.
The concept of marobashi can be found in the Scroll of Empi written by the founder: “There are four approaches to swordplay. They are attacking, waiting, attacking from the front, and attacking from the back. We should not attach ourselves to only one way. We should turn and change our approach depending on the opponent’s situation and take appropriate measures just as a one reads the wind and sets one’s sails, or spots a rabbit and releases a hawk.”.
To utilize marobashi we must have mukei-no-kurai, which means having no preconceptions. The mind and body should have no fixed intention in advance and we should face each situation with a neutral mind, so we can perceive the countless changes of an opponent. We prefer to elicit an action from the opponent and then respond in accordance to this action (katsuninken), rather than trying to defeat the opponent by using more power and/or speed (setsunintō).
Shinjitsu no hito is a phrase written in the license issued to Yagyū Sekishūsai from the founder. Shinjitsu no hito means a sincere person without egotism. The license says, “Only a true person can learn further”. This means that only a true person can receive the secrets of Heihō. Sekishūsai expresses this in one of his 100 tankas (poems) about heihō, stating that if students do not possess the five virtues, they should not be taught the secrets of swordplay. The five virtues are thinking about others deeply (jin), righteousness (gi), courtesy (rei), the wisdom to judge correct from incorrect (chi) and sincerity (shin). This is the stern admonishment Sekishūsai left for the students of this school.
Sekishūsai also left three additional guidelines in the Yagyū Family Constitution. The first is that if you find someone who knows something that you do not, you should ask for instruction. The second is that you should not compete with other schools. The third is that, instead of competing with others, you should strive to surpass today yourself of yesterday.