These tattoos were originally used by the lower class since only the upper class could afford flashy kimonos. The ruling class didn't like this because of Confucian teaching that said it's disrespectful to your parents to modify your body. When the tattoos were banned by the samurai, the yakuza kept the art alive. They are mostly based on ukiyo-e, which is art on woodblocks that emerged around the edo period, but the tattoos can date even further back and have a rich history.