The standard large ukiyo-e print format is called ōban.
The term ōban means “large print” and generally refers to a sheet measuring about 39 by 26 centimetres, though exact dimensions varied by period and publisher. It became the dominant format for many single-sheet landscapes, actor portraits, and pictures of beautiful women during the Edo and Meiji periods.
Ōban should not be confused with hosoban, a narrow vertical format, or hashira-e, a tall print designed to resemble a pillar hanging. Chūban was a smaller format, usually roughly half the size of an ōban. Japanese print sizes were practical categories rather than perfectly standardized measurements, because paper was trimmed and formats changed over time.
The format mattered commercially: an ōban provided enough surface for detailed line work, multiple color blocks, inscriptions, and elaborate backgrounds while remaining suitable for affordable mass production.