On October 21, 1600, Miyamoto Musashi took part in the Sekigahara Battle, which was a war between the Toyotomi and Tokugawa clans for the unification of Japan.
Because his family was allied to the Toyotomi Clan, Musashi fought for Toyotomi Hideyoshi's army. During the Battle of Sekigahara in July 1600, Musashi took part in the attack on Fushimi Castle (Fushimi-jo or Fishimijo). He also participated in the defense of the besieged Gifu Castle (Gifu-jo) in the Gifu Prefecture. Even at relatively young age, Miyamoto Musashi fought vigorously, and he escaped the defeat of Hideyori's forces unharmed.
Three years later, Musashi fought against the army of Ieyasu Tokugawa who, after the victory of his troops, became shogun and established the Tokugawa Era (also known as the Edo period), which would last for 266 years.
After the battle, Miyamoto Musashi wandered across Japan perfecting his kenjutsu skills, having many duels, and meeting many masters of the sword.
After disappearing from the records for a while, Musashi arrived in Kyoto around the age of 21 or 22. Upon arriving in Kyoto, he began a famous a series of duels with the famous Yoshioka Clan. The clan was famous for its Yoshioka Ryu, a style of kenjutsu which was famous all across Japan and had been founded around 1532 by Yoshioka Kempo.
The kenjutsu style of the Yoshioka Clan was part of the Kyohachiryu, which meant that it was one of the eight major kenjutsu styles in Kyoto. The swordsmen of the Yoshioka Clan had been instructors for the powerful Ashikaga Family for four generations.
Yoshioka Seijuro, master of the Yoshioka School and head of the Yoshioka family, was challenged to a duel by Musashi. Seijuro eagerly accepted the duel, and both men decided to fight outside of Rendaiji Temple in Northern Kyoto on March 8, 1604.
As a part of his strategy, Miyamoto Musashi arrived late on the day of the fight. Seijuro was greatly irritated and lost his temper with Musashi, judging his behavior to be unacceptable. As they had previously agreed, the duel was to be fought with a bokuto (wooden sword) and the winner would be declared by a single blow.
They faced off and took the on-guard position. In an instant, Musashi hit Seijuro's shoulder with his wooden sword, knocking him off his feet and breaking his left arm. Musashi won the duel. With his soul tormented by dishonor, Yoshioka Seijuro retired from the warrior's life and became a monk in a Zen order.
Seijuro's brother, a brilliant swordsman named Yoshioka Denshichiro, became the head of the Yoshioka Family and later challenged Musashi to regain his family's honor and avenge his brother's defeat.
The duel was to be held at Sanjusangendo (see image), a Buddhist temple in the Higashiyama District of Kyoto, which was famous for its thousand statues of Kannon, the Shinto goddess of mercy and compassion.
As with his last duel, Miyamoto Musashi once again arrived late to fight Denshichiro. This time, it was a duel to the death. Musashi was armed with a bokuto and Denshichiro had a staff reinforced with steel rings.
Musashi was mentally, technically and physically stronger than his skilled opponent. Seconds after the beginning of the duel, Musashi hit Denshichiro with his wooden sword, killing him instantly with a single blow to the head.
The Yoshioka Clan had become desperate with the death of Denshichiro Yoshioka, who was now the second head of the family to be defeated by Miyamoto Musashi. The head of the clan was now the 12-year old Yoshioka Matashichiro, who, like his predecessors, also challenged Musashi to a duel. At this point, the Yoshioka clan was ready to do anything to gain back their honor and reputation. They had to take Musashi down.
This time, the Yoshioka Clan decided that the duel between Yoshioka Matashichiro and Miyamoto Musashi was to be fought at night. It was unusual for nighttime duels to be requested, so Musashi, being suspicious, decided to arrive at the rendezvous point well before the time of the fight, and he waited in hiding for his enemy to come.
The boy arrived dressed in full armor with a party of well-armed retainers, archers, riflemen and swordsmen who were all determined to kill Musashi. They all hid nearby, and set a trap for Musashi, with Matashichiro acting as bait.
Musashi watched the action as he waited patiently, concealed in the bushes. When the moment was right, he left his hiding place, drew his sword, and ran towards the boy, cutting off his head. Seconds later, Matashichiro's men gathered around Musashi, trying to stop him from escaping.
"Many historians agree that Musashi discovered the superiority of weilding two swords during this battle."
Greatly outnumbered and with both swords in hand, Musashi cut a path through the rice fields, making his way to escape while being attacked by dozens of men. With the death of Yoshioka Matashichiro, the Yoshioka Clan Kenjutsu School was annihilated.
Many historians agree that Musashi discovered the superiority of weilding two swords during this battle. The use of two swords simultaneously was totally foreign to the conventions of kenjutsu, as samurai traditionally only fought with the long sword (Katana) held in two hands. Musashi's experience forged the path to what would become known as the Nito-Ryu style of kenjutsu.