Ruffians, in Japanese folklore, appeared alongside Samurai, were excellent with swords and appeared fierce, strong and always tattooed. Ruffians have inspired many a tattoo, not just in Japanese culture but in all cultures. shunga art is filled with ruffians, wielding their swords or clenching them between their teeth.
Ruffians were also famous swordsmen, like the Samurai, Ninja, Warriors and Monks. They were unflinchingly brave and loyal and were always heroes, which is why they are so popular in shunga art and also, as tattoos. Ruffians were highly trained, could fight anything and everybody, were filled with life and colour, and nothing scared them.
Books have been written about Japanese swordsmen, Samurai and Ruffians, the most famous being The Suikoden, following the adventures of 108 honourable ruffians and bandits.
Ruffians were just that, ruffians, rarely coming from Japanese nobility. But they were sharp, strong, bright, loyal and courageous. Hence they are a large part of shunga art.