A shogun was a title given to a ruler in historical Japan on the planet Earth.
Orions tended to think that 23rd century Earth was still ruled by shoguns after experiencing a craze for 20th century Earth culture that began in the mid-22nd century, after the UNSS Marco Polo sold them a cargo of artifacts from that era on reference stardate 0/7907.27 (c. 2150). (FASA RPG module: The Orions: Book of Common Knowledge)