Which shogunate ruled Japan for over 250 years until 1868?

The Tokugawa, from 1603, and the peace they imposed was almost total - two and a half centuries with essentially no internal war, which is difficult to match anywhere. The price was a controlled society: a rigid class order, Christianity banned, and foreign contact restricted to a single Dutch trading post on an artificial island at Nagasaki.

The mechanism of control was ingenious and expensive. Every regional lord was required to spend alternate years in the capital and to leave his family there permanently - hostages in all but name - and the constant processions and dual households bankrupted the nobility, built the roads, and made Edo the largest city in the world.

It ended when four American warships arrived in 1853 and demanded trade. The regime's inability to refuse exposed it, and reformist samurai from outlying domains - Satsuma and Choshu, the very ones excluded from power after Sekigahara 250 years earlier - overthrew it in the name of restoring the emperor. Japan then industrialised at a speed nobody anticipated, and within fifty years had defeated Russia at sea.