Yoshihiko Shirakura(Japanese Shunga of Kuniyoshi,
2012, Heibonsha Ltd., Tokyo)
dates this series to 1854-1860, but Ofer Shagan (Japanese Erotic Art,
2013, Thames & Hudson, London)
dates the series to 1838.Each page of this three-volume set is approximately 10 by 7¼ inches or 25.5 by 18.5 centimeters, a size known
as ôban.I am grateful to Robert
Pryor for assisting with this section.