The common large ukiyo-e print size measuring about 39 by 26 centimeters is the Ōban format.
Ōban, meaning “large format,” became the standard size for many full-colour ukiyo-e prints, especially from the late 18th century onward. Its approximate dimensions are often given as about 39–39.5 centimetres high by 26–27 centimetres wide, although handmade paper, trimming, period, and publisher could produce small variations.
The format was closely tied to the way hōshō paper was prepared and cut. A large ō-bōshō sheet could be divided to produce an Ōban sheet, making the format practical for mass production while still providing enough surface for detailed figures, landscapes, and colour effects. Famous actor prints, beauty portraits, and landscape series frequently used it.
Ōban is easy to confuse with Chūban, which is smaller, or Hashira-e, the tall, narrow “pillar print” format. Koban is smaller still. An Ōban could also be printed vertically or horizontally, so the orientation does not determine the format. Three Ōban sheets placed side by side form a common triptych.