The ages of humankind are designated by the material with which they made tools and weapons: stone, bronze, and iron. Remnants of these tools and weapons, found in archaeological excavations, are often the earliest evidence of existence in a place, especially before humans were able to express (and depict) themselves in words or art. Artistic depictions would follow, and then written ones, but both several thousands of years later. A wood, stone, or metal club, a stone or metal spearhead or arrowhead, a metal dagger or sword – and this appears to have been the progression – all could be used for hunting, likely their main function in pre-agricultural societies.

Anthropologists believe that the Japanese archipelago was settled by migrants from the Asian mainland sometime between 140,000 and 500,000 years ago, when falling global temperatures trapped water in glaciers and the polar ice caps, causing sea levels to drop 120 m or more below their present levels, and opening land bridges to Siberia and the Korean peninsula. Permanent village settlements and a cultural complex known as the Jōmon, after the distinctive, cord-marked slab pottery found at most sites, appeared between 14,500 and 10,000 bce. Around 1,000 bce, a new wave of immigrants spread outward from northern Kyushu, intermingling with the Jōmon peoples and displacing their civilization with a new one, which archaeologists have dubbed Yayoi after the location of the first site discovered, in Tokyo in 1884. The newcomers brought with them bronze- and iron-working skills, advanced agricultural techniques, and more sophisticated forms of political organization.

Over a span of three and a half centuries (1200–1550) Japan experienced profound transformations in the institutions, ideals, and methods of war. Originally a limited, clearly defined and extraordinary event, warfare became an endemic and encompassing element of life in the mid sixteenth century. Earlier, small bands of mounted warriors, skilled in archery, arrived in camp and departed as they saw fit, for no institutional mechanisms existed for them to supply themselves or their followers with food and materials of war. By the sixteenth century, however, powerful magnates (daimyō) were capable of supplying and maintaining large armies, numbering in the thousands, largely composed of pike-wielding foot soldiers.

Weapons and armor are significant objects in the Homeric epics as well as in the archaeological record of Late Bronze and Early Iron Age Greece. The relationship between these objects in these time periods and their archaeological contexts suggests as much about early Greek society as it does about warfare.