Kaō

A kaō (花押) is a stylized signature or a mark used in place of a signature. Kaō first appeared in China during the Tang Dynasty, and began to be used in Japan during the Heian period. Though their use became far less widespread after the Edo period, they continue to be used even by some contemporary politicians and other famous individuals. The reading and identification of individual kaō often requires specialist knowledge; whole books devoted to the topic have been published.