五輪書
In his later years, Musashi said in his "The Book of Five Rings": "When I apply the principle of strategy to the ways of different arts and crafts, I no longer have need for a teacher in any domain." He proved this by creating recognized masterpieces of calligraphy and classic ink painting. His paintings are characterized by skilled use of ink washes and an economy of brush stroke. He especially mastered the "broken ink" school of landscapes, applying it to other subjects, such as his "Kobokumeikakuzu" ("Shrike Perched on a Withered Branch"; part of a triptych whose other two members were "Hotei Walking" and "Sparrow on Bamboo"), his "Hotei Watching a Cockfight", and his "Rozanzu" ("Wild Geese Among Reeds"). The Book of Five Rings advocates involvement in calligraphy and other arts as a means of training in the art of war.