The large boat-shaped bowl is decorated in the foreground with the design of a bat spreading its wings and in the back with a tomoe design (double interlocking commas). The bat motif portion was made transparent by scraping off the color overlay entirely. Then by grinding and polishing the glass into the form of a convex lens, a beautiful gradation of blue is displayed on the body. To indicate that this is a boat, transparent bands form the sides and bottom toward the tomoe design in back. This bold, ingenious design was used in several brush-rinsing bowls of transparent colorless glass made in the Edo period. This is a well-known masterpiece of Satsuma cut glass.