Details about the early life of the legendary samurai Miyamoto Musashi are difficult to verify as all that Musashi left behind were writings related to the kenjutsu sword-fighting technique and strategy.
Most Japanese historians agree that Miyamoto Musashi was born around 1584 (the Year of the Monkey), which was a period of turmoil as the country had been thrown into civil war with different Japanese warlords fighting for supremacy over the Japanese territory.
Miyamoto Musashi was born into a samurai family in Miyamoto village in the Harima province. His full name was Shinmen Musashi no Kami Fujiwara no Genshin, and his childhood name was either Bennosuke or Takezo, it is unknown which. Musashi took his name from his birthplace, Miyamoto village.
Musashi's father was a samurai named Shinmen Munisai, who was an accomplished swordsman and an expert in kenjutsu (swordmanship) and juttejutsu. Munisai taught kenjutsu and juttejutsu to Musashi at a young age, as was the tradition in samurai families, and the young Musashi showed an early talent for kenjutsu. Shinmen Munisai's father, Hirata Shogen, was a vassal of Lord Shinmen Iga no Kami of Mimasaka Province.
Miyamoto Musashi's mother died soon after he was born, so he was raised by his step-mother, a woman named Toshiko whom very little is known about. When his father, Munisai, divorced Toshiko, Musashi was sent to live with his uncle Dorin, a monk from the Shoreian temple. While staying with the monk, he was taught Zen Buddhism and basic skills, such as reading and writing.
Munisai was very a harsh, strict and demanding man, especially towards his son. Their relationship was tumultuous and Munisai showed no love for the young Musashi. It is unknown what exactly happened, but when Musashi was around 9 or 10 his father either died or completely abandoned the boy. Some historians say that Shinmen Munisai was killed during a duel with a swordsman named Ganryu Yoshitaka.
According to the personal details given by Miyamoto Musashi in his "Book of Five Rings", the "Go Rin No Sho", Musashi had his first duel at the age of thirteen. His opponent was a samurai from the Tajima Province, a man named Arima Kibei, who was a swordsman from the Shinto-Ryu Kenjutsu school. Seconds after the beginning of the fight, Musashi thew Arima on the ground and hit him with his bokuto (a wooden sword, also known as a bokken). Arima Kibei died vomiting blood.
Musashi left the temple when he was between 16 or 20 years old (this is unclear), to perfect his kenjutsu technique and his skills with the Katana, and to follow his ambition to become Japan's greatest swordsman.