is a text on kenjutsu and the martial arts in general, written by the Japanese swordsman Miyamoto Musashi around 1645. Many translations have been made, and it garnered broad attention in East Asia and worldwide. For instance, some foreign business leaders find its discussion of conflict to be relevant to their work. The modern-day Hyōhō Niten Ichi-ryū employs it as a manual of technique and philosophy.
Musashi establishes a "no-nonsense" theme throughout the text. For instance, he repeatedly remarks that technical flourishes are excessive, and contrasts worrying about such things with the principle that all technique is simply a method of cutting down one's opponent. He also continually makes the point that the understandings expressed in the book are important for combat on any scale, whether a one-on-one duel or a massive battle. Descriptions of principles are often followed by admonitions to "investigate this thoroughly" through practice rather than trying to learn them by merely reading.
Musashi describes and advocates a two-sword fencing style (nitōjutsu): that is, wielding both katana and wakizashi, contrary to the more traditional method of wielding the katana two-handed. However, he only explicitly describes wielding two swords in a section on fighting against many adversaries. The stories of his many duels rarely refer to Musashi himself wielding two swords, although, since they are mostly oral traditions, their details may be inaccurate. Musashi states within the volume that one should train with a long sword in each hand, thereby training the body and improving one's ability to use two blades simultaneously.
The five books
Go Rin No Sho are the teachings which Musashi preached to his students in his own dōjō. Though ideas are taken from other sources, the text is predominantly seminal. The five "books" refer to the idea that there are different elements of battle, just as there are different physical elements in life, as described by Buddhism, Shinto, and other Eastern religions. The five books below are Musashi's descriptions of the exact methods or techniques which are described by such elements.
The term Ichi School refers to "Niten No Ichi Ryu" or "Ni-Ten Ichi Ryu", which literally translates to "Two Heavens, One School". Alternative translations include: "Two Swords, One Spirit", and "Two Swords, One Entity". The translation, "Two Swords, One Dragon" was thought to be a misinterpretation of the Kanji word Ryu.
The Book of Earth chapter serves as an introduction, and metaphorically discusses martial arts, leadership, and training as building a house. The Book of Water chapter describes Musashi's style, Ni-ten ichi-ryu, or "Two Heavens, One Style". It describes some basic technique and fundamental principles. The Book of Fire chapter refers to the heat of battle, and discusses matters such as different types of timing. The Book of Wind chapter is something of a pun, since the Japanese character for "wind" can also mean "style" (such as, of martial arts). It discusses what Musashi considers to be the failings of various contemporary schools of sword fighting. The Book of the Void chapter is a short epilogue, describing, in more esoteric terms, Musashi's (probably) Zen-influenced thoughts on consciousness and the correct mindset.
The Book of Earth
The Earth book, according to "Go Rin No Sho", refers expressly to the strategy taught by Musashi at the Ichi School. It is said to be how to distinguish the Way through "Sword-Fencing", or "Swordsmanship". The idea of strategy would be encouraged to be very astute in their study and strategy:
Know the smallest things and the biggest things, the shallowest things and the deepest things. As if it were a straight road mapped out on the ground... These things cannot be explained in detail. From one thing, know ten thousand things. When you attain the Way of Strategy there will not be one thing you cannot see. You must study hard.
Upon their mastery of the strategy and timing listed in the five books, Musashi states that people will be able to defeat ten men as easily as they could defeat one, and asks: "When you have reached this point, will it not mean that you are invincible?"
The strategies listed in this discipline or book relate to situations requiring different weapons and tactics, such as indoor weapons. Musashi states that the use of glaive-like naginata and spears are purely for the field, whereas the longsword and accompanying short-sword can be used in most environments, such as on horseback or in fierce battle.