Before shibari became an art, and later a fetish (kinbaku), it originated in Japan as a means of securing prisoners (hojōjutsu). It was later eroticized by artists on wood blocks and tapestry and became more of a fetish in the 18-1900s.Samurai were required to tie someone in a manner that would prevent injury and prevent escape. The techniques were kept in secrecy and like anything Japanese, the tying required a pleasing aesthetic.
Still, today, police in Japan are trained in hojōjutsu and keep lengths of hemp rope on them for restraint purposes.In the evolution of shibari as art, the latest iteration is the “suspension.”I hope this explanation was helpful. Please feel free to ask if you have any more questions.