Lit. medium-size format. A size of *ukiyo-e 浮世絵 print. The term chūban is used for certain formats cut from three different types of paper in different sizes.
1 A quarter of a standard-sized sheet called *ōbōsho 大奉書. Also called yotsugiriban 四つ切判. Approximately 26 × 19.5 cm. Ōbōsho was the common type of chūban used in the early days of full-color woodblock prints *nishiki-e 錦絵, until the 1770s when *ōban 大判 became the standard format. Isoda Koryūsai 磯田湖龍斎 (active in the latter half of the 18th century) and Torii Kiyonaga 鳥居清長 (1752-1815) commonly used ōbōsho.
2 A quarter of a sheet of ōhirobōsho 大広奉書. Also called harunobuban 春信判 because this type of format was extensively used for the prints of Suzuki Harunobu 鈴木春信 (1725-70) around 1765. Approximately 29 × 22 cm. Slightly larger than above-mentioned chūban of ōbōsho.
3 Also called *aiban 間判. A half sheet of a special type of large format *ōban 大判. Approximately 21.5 × 30 cm. Used for the scarlet pictures *beni-e 紅絵 actor prints *yakusha-e 役者絵 by Torii Kiyonobu 鳥居清信 (1664-1729) and Kiyomasu 清倍 (active in the early 18th century) in the 1720s.