were the hereditary military nobility and officer caste of medieval and early-modern Japan from the 12th century to their abolition in the 1870s. They were the well-paid retainers of the daimyo (the great feudal landholders). They had high prestige and special privileges such as wearing two swords. They cultivated the bushido codes of martial virtues, indifference to pain, and unflinching loyalty, engaging in many local battles. During the peaceful Edo era (1603 to 1868) they became the stewards and chamberlains of the daimyo estates, gaining managerial experience and education. In the 1870s they were 5% of the population. The Meiji Revolution ended their feudal roles and they moved into professional and entrepreneurial roles. Their memory and weaponry remain prominent in Japanese popular culture.

Martial arts are codified systems and traditions of combat practiced for a number of reasons such as self-defense; military and law enforcement applications; competition; physical, mental and spiritual development; and entertainment or the preservation of a nation's intangible cultural heritage. Although the term martial art has become associated with the fighting arts of East Asia, it originally referred to the combat systems of Europe as early as the 1550s. The term is derived from Latin and means "arts of Mars", the Roman god of war. Some authors have argued that fighting arts or fighting systems would be more appropriate on the basis that many martial arts were never "martial" in the sense of being used or created by professional warriors.