Miyamoto Musashi

Context: Regardless of the truth about Musashi's ancestry, when Musashi was seven years old, the boy was raised by his uncle, Dorinbo (or Dorin), in Shoreian temple, three kilometers (~1.8 mi.) from Hirafuku. Both Dorin and Tasumi, Musashi's uncle by marriage, educated him in Buddhism and basic skills such as writing and reading. This education is possibly the basis for Yoshikawa Eiji's fictional education of Musashi by the historical Zen monk Takuan. He was apparently trained by Munisai in the sword, and in the family art of the jutte. This training did not last for a very long time, as in 1589, Munisai was ordered by Shinmen Sokan to kill Munisai's student, Honiden Gekinosuke. The Honiden family was displeased, and so Munisai was forced to move four kilometers (~2.5 mi.) away to the village of Kawakami.  In 1592, Munisai died, although Tokitsu believes that the person who died at this time was really Hirata Takehito.  Musashi contracted eczema in his infancy, and this adversely affected his appearance. Another story claims that he never took a bath because he did not want to be surprised unarmed. While the former claim may or may not have some basis in reality, the latter seems improbable. An unwashed member of the warrior caste would not have been received as a guest by such houses as Honda, Ogasawara, and Hosokawa. These and many other details are likely embellishments that were added to his legend, or misinterpretations of literature describing him.  His father's fate is uncertain, but it is thought that he died at the hands of one of Musashi's later adversaries, who was punished or even killed for treating Musashi's father badly. However, there are no exact details of Musashi's life, since Musashi's only writings are those related to strategy and technique.  I have trained in the way of strategy since my youth, and at the age of thirteen I fought a duel for the first time. My opponent was called Arima Kihei, a sword adept of the Shinto ryu, and I defeated him. At the age of sixteen I defeated a powerful adept by the name of Akiyama, who came from Tajima Province. At the age of twenty-one I went up to Kyoto and fought duels with several adepts of the sword from famous schools, but I never lost.  According to the introduction of The Book of Five Rings, Musashi states that his first successful duel was at the age of 13, against a samurai named Arima Kihei who fought using the Kashima Shinto-ryu style, founded by Tsukahara Bokuden (b. 1489, d. 1571). The main source of the duel is the Hyoho senshi denki ("Anecdotes about the Deceased Master"). Summarized, its account goes as follows:  In 1596, Musashi was 13, and Arima Kihei, who was traveling to hone his art, posted a public challenge in Hirafuku-mura. Musashi wrote his name on the challenge. A messenger came to Dorin's temple, where Musashi was staying, to inform Musashi that his duel had been accepted by Kihei. Dorin, Musashi's uncle, was shocked by this, and tried to beg off the duel in Musashi's name, based on his nephew's age. Kihei was adamant that the only way his honor could be cleared was if Musashi apologized to him when the duel was scheduled. So when the time set for the duel arrived, Dorin began apologizing for Musashi, who merely charged at Kihei with a six-foot quarterstaff, shouting a challenge to Kihei. Kihei attacked with a wakizashi, but Musashi threw Kihei on the floor, and while Kihei tried to get up, Musashi struck Arima between the eyes and then beat him to death. Arima was said to have been arrogant, overly eager to battle, and not a terribly talented swordsman.  Musashi created and refined a two-sword kenjutsu technique called niten'ichi (Er Tian Yi , "two heavens as one") or nitoichi (Er Dao Yi , "two swords as one") or 'Niten Ichi-ryu' (A Kongen Buddhist Sutra refers to the two heavens as the two guardians of Buddha). In this technique, the swordsman uses both a large sword, and a "companion sword" at the same time, such as a katana with a wakizashi.  The two-handed movements of temple drummers may have inspired him, although it could be that the technique was forged through Musashi's combat experience. Jutte techniques were taught to him by his father -- the jutte was often used in battle paired with a sword; the jutte would parry and neutralize the weapon of the enemy while the sword struck or the practitioner grappled with the enemy. Today Musashi's style of swordsmanship is known as Hyoho Niten Ichi-ryu.  Musashi was also an expert in throwing weapons. He frequently threw his short sword, and Kenji Tokitsu believes that shuriken methods for the wakizashi were the Niten Ichi Ryu's secret techniques.  Musashi spent many years studying Buddhism and swordsmanship. He was an accomplished artist, sculptor, and calligrapher. Records also show that he had architectural skills. Also, he seems to have had a rather straightforward approach to combat, with no additional frills or aesthetic considerations. This was probably due to his real-life combat experience; although in his later life, Musashi followed the more artistic. He made various Zen brush paintings, calligraphy, and sculpted wood and metal. Even in The Book of Five Rings he emphasizes that samurai should understand other professions as well. It should be understood that Musashi's writings were very ambiguous, and translating them into English makes them even more so; that is why so many different translations of The Book of Five Rings can be found. To gain further insight into Musashi's principles and personality, one could read his other works, such as Dokkodo and Hyoho Shiji ni Kajo. CANNOTANSWER

Question: what was one of Miyamoto Musashi teachings?
Answer: The Book of Five Rings