The crab has been a symbolic animal to a variety of different cultures throughout the world. Heikegani is a species of crab native to Japan, with a shell that bears a pattern resembling a human face which many believed to be the face of an angry samurai hence the nickname Samurai Crab.
It is locally believed that these crabs are reincarnations of the spirits of the Heike warriors defeated at the Battle of Dan-no-ura as told in The Tale of the Heike.
There is a vast variety of different species of crabs. The crab tattoo can portray any type of the associated crab species. Crab tattoos bring plenty of different options for the tattoo artist and the wearer. Size, shape, design and color vary, so you have many options to consider with the crab tattoo.
Remember though, in the end, your tattoo symbolizes what you want it to.