Although systematic training in the use of weapons, and methods for employing them in warfare existed long before, it is generally believed that the development of martial traditions, schools, or styles (ryu-ha) did not arise until after the end of the Heian period (794-1185). Central to this training was study of the bow (yumi), the sword (tachi), and the spear (yari). Initially, these weapons were not studied in separate arts. Rather, since the need was to prepare for battlefield combat, many different weapons and strategic and tactical skills were taught as part of comprehensive systems (sogo bujutsu). From the middle of the Muromachi period (ca. 1480) to the beginning of the Tokugawa period (ca. 1605) people gradually began to specialize in a particular weapon or system, particularly the bow, spear, sword, grappling and horsemanship. Warriors gathered in family-centered groups or trained with other members of their local domains. As the techniques and methods of these groups became more and more individuated, or as teachers gained particular insights into the essential nature and principles of combat, there arose discrete martial “traditions” or “styles” or “schools” (bujutsu ryu-ha). This began happening at the beginning of the Keicho era (ca. 1600), picked up impetus throughout the Tokugawa period (1600-1868), and has continued even into the twentieth century.