The Utagawa school was a group of Japanese woodblock print artists, founded by Toyoharu. His pupil, Toyokuni I, took over after Toyoharu's death and raised the group to become the most famous and powerful woodblock print school for the remainder of the 19th century.
The school became so successful and well known that today more than half of all surviving ukiyo-e prints are from it.
It was a Japanese custom for successful apprentices to take the names of their masters. In the main Utagawa school, there was a hierarchy of gō (art-names), from the most senior to junior. As each senior person died, the others would move up a step.