Battle of Sekigahara Tactical System

Timeline

1. 1600Mino and Ōmi · Ōmi ProvinceThe Eastern Army concentrated from the direction of Edo and the Western Army from Osaka; both sides used strongpoints such as Fushimi Castle and Gifu Castle to control transport lines and grain supplies. The tactical focus was on seizing the Sekigahara pass first, cutting off the opponent's supplies, and mobilizing daimyo along the route to provide provisions and arquebus ammunition, reflecting maneuver warfare supported by a castle network.
2. 1600Sekigahara battlefield · SekigaharaBoth sides deployed large numbers of arquebusiers and spear ashigaru, adopting three-rank or continuous volley formations, combining firepower suppression with flanking maneuvers. The Eastern Army deployed dense arquebus positions in front of its main camp, while the Western Army relied on flanking assaults by the Mōri, Kobayakawa, and other units; the mixed deployment of firearms and cold weapons formed the firepower basis of the decisive battle.
3. 1600Sekigahara battlefield · SekigaharaThe battle began in fog on the day of the decisive engagement; Kobayakawa Hideaki's forces defected to Ieyasu's side in front of the lines, and the Western Army's flank collapsed. The tactical system here manifested as coalition politics and prior subversion, coordination via signal flags and messengers, and a chain rout after the collapse of the main camp, deciding the fate of the whole country within hours and becoming the largest civil war decisive battle in Japanese history.