In a Japanese Shinto wedding, the ritual of taking three sips from each of three sake cups is called san-san-ku-do.
The name combines Japanese words for “three,” “three,” and “nine,” referring to the three cups and the three sips taken from each. The couple drinks in turn, creating a formal bond between them and, traditionally, between their families.
The cups are usually called sakazuki and are arranged in graduated sizes. The smallest cup is associated with the past, the middle cup with the present, and the largest with the future in some explanations of the ceremony. Interpretations and exact procedures can vary by shrine and wedding school.
San-san-ku-do is not simply a toast like a Western champagne toast. It is a prescribed ceremonial exchange of sake, and the number nine is traditionally treated as auspicious because it is odd. Modern Japanese weddings may combine Shinto customs with Western-style receptions.