sakoku

Within a couple decades after Commodore Perry compelled Japan to open its doors to the West with the Treaty of Shimoda, Japanese society was beginning to relax its taboos against the consumption of meat other than seafood signalled by Emperor Mutsuhito’s 1872 New Year’s repast of beef—which caused much consternation among devout Buddhists who had helped cultivate the prohibition for over twelve centuries.
The Meiji administration changed its policy of isolation and was eager to adopt Western ways and technologies, effectively rescinding a decree from Emperor Tenmu in the seventh century not to eat useful animals during the farming season, which came to be a general avoidance (a heavy penance was put in place or transgression) for practical reasons as well as the belief in transmigration of the soul and the chance that would could be reincarnated as a cow or boar.