At that time, books and ukiyo-e were censored by the Edo shogunate, but almost all namazu-e were illegally published without applying for permission and many of them do not have signatures of the creator or painter to avoid regulation.
当時の書籍や浮世絵は江戸幕府の検閲を受けていたが、鯰絵はほぼすべてが無届けの不法出版であり、取締まり逃れのため作者や画工の署名が無いものが多い。