National Isolation ("Sakoku" in Japanese) refers to the policy of seclusion by which the Edo Bakufu (Japanese feudal government headed by a shogun) prohibited Japanese citizens from going abroad, while imposing restrictions on diplomatic exchanges and trade with foreign countries.
鎖国（さこく）は、江戸幕府が日本人の海外交通を禁止し、外交・貿易を制限した政策のこと。