Often translated as "national seclusion," sakoku is a Japanese word which literally means "chained country," and refers to the period from 1639 to 1854 when Japan was closed to all outside contact with the exception of a tiny Dutch trading post on the island of Dejima off Nagasaki and limited contact with Chinese traders via the Ryukyu Islands and Korean traders via Tsushima island.
The sakoku policy was implemented by the Tokugawa shogunate over a period of six years from 1633-1639 by means of five National Seclusion Edicts. The first edict (1633) imposed severe restrictions on foreign trade and overseas travel by Japanese. The second and third edicts (1634 and 1635), banned overseas travel by Japanese altogether, and prescribed a death sentence for any Japanese attempting to leave or reenter the country. The fourth edict (1636) banned all "southern barbarians" (ie Spanish and Portuguese) from setting foot on Japanese soil, on pain of death. The fifth and final edict (1639), issued in the aftermath of the Shimabara Rebellion of Christianized Japanese peasants, largely completed the seclusion policy, banning Spanish and Portuguese ships from even entering Japanese waters. A less significant 1641 edict, transfering the Dutch port from Hirado to Nagasaki, is sometimes considered the sixth national seclusion edict.
The sakoku policy persisted until 1854, when Commodore Matthew Perry led a flotilla of American warships into Edo Bay, forcibly precipitating The Opening of Japan.