The collection, appreciation, and display of petrified wood has been part of the Japanese viewing stone culture for many decades, possibly dating back to Tokugawa Tsunayochi, the 5th Shogun of the Tokugawa period. While pieces of petrified wood have been found in different regions of Japan, the ones found in Gifu and Aichi prefectures are considered as the most desirable. The primary attraction of these stones is their color; the red, green, yellow, black, white, pink, or multicolored stones are the most highly prized.