Fumie (literally, "stomping on the image"), was a practice used in Edo Period Japan to determine if people were secretly practicing Christianity, a religion which had been banned from the country on pain of death. Every so often, local officials would be required by the Tokugawa shogunate to go from household to household and force all members of the family, even small children, to step on an image of Jesus Christ on the cross or the Virgin and Child. Those who refused to step on the Christian images were considered to be Christians and were tortured until they converted or executed, many by being thrown into the Mount Unzen volcano near Nagasaki.
Stepping on something with the sole of one's foot was a sign of extreme disrespect in Japanese culture, so the logic was that no true believer would be able to do such a thing to their god. Nevertheless, a small number of secretly practicing Christians found a way to grit their teeth and bear the fumie, and thus managed to survive in Japan undetected for centuries until they were able to reemerge from secrecy in the Meiji Period.
The practice of fumie was particularly prevalent in Kyushu, which had been a bastion of Christian sentiment in the early Edo period. Perhaps somewhat surprisingly, the images used were generally of very high artistic quality, carved from stone or printed from woodblocks by professional artists from European models. Few actual fumie images remain to this day, however, as they were not considered valuable or worth saving.