Masu were standard sake drinking vessels that originated in the Edo shogunate of the 1600s. Nowadays small ceramic or glass cups tend to be used day-to-day, with masu generally being utilised during special occasions and ceremonies. Wooden masu cups such as this are considered a great luxury and a symbol of good luck. For a great selection of sake drinking vessels, as well as other Japanese serveware, take a look at japancentre.com's Dining section.