Later Life and Death.

In 1640, Musashi Miyamoto officially became the retainer of Hosokawa Tadatoshi, Lord of Kumamoto, and received 17 loyal retainer to his service and Chiba Castle in as his residence.

The following year, in 1641, Musashi wrote for Hosokawa Tadatoshi the "Hyoho Sanju Go", the "Thirty-five Instructions on Strategy", a book about his fighting philosophy and technique. This book formed the basis of his Masterpiece, the famous Gi Rin No Sho, a book that will come to life two years later.

In 1642, Musashi suffered attacks of neuralgia, a painful disorder of the nerves. Feeling that his end was near, Musashi retired to a cave named Reigando, close to Kumamoto, in 1643 to write his Go Rin No Sho, The Book of Five Rings. He finished it in the second month of 1645 and gave it to his closest student.

"Musashi retired to a cave (...) in 1643 to write his Gorin-No-Sho, The Book of Five Rings."

On the twelfth day of the fifth month, he finished writing 'Dokkodo', ("The Way of Walking Alone"), a book on self-discipline, a guide to future generations.

He died in Reigando cave around the nineteenth of the fifth month, or possibly June 13, 1645.