Before Sakoku, Japan was in a large state of civil unrest, they were culturally unstable and felt threatened by new rising religions such as Christianity. To the Tokugawa Shogun, there were many things to fear. They felt that Japan was being severely influenced by the outside world and that their culture and/or religion would be erased. The Tokugawa Shogun felt that the Japanese culture was in danger. They thought that in order to keep their power and Japan in check, they had to find a way to stop this influence.
Tokugawa Symbol, Rekishinihon, 2013
This led Tokugawa Iemitsu to placing the edicts that started Sakoku. Not only did these edicts keep the Japanese from leaving, but they kept other religions, cultures, influences, and people that weren't Japanese out of Japan. Almost all Japanese people weren’t allowed communication with the outside world. Due to this, Japan went into almost complete isolation. This isolation was given the name Sakoku, meaning chained country.