Battle of Sekigahara The was a decisive battle on October 21 , 1600 ( " Keichō 5 , 15th day of the 9th month " ) which cleared the path to the Shogun ate for Tokugawa Ieyasu . Though it would take three more years for Ieyasu to consolidate his position of power over the Toyotomi clan and the daimyo , Sekigahara is widely considered to be the unofficial beginning of the Tokugawa bakufu , the last shogun ate to control Japan . Japan had a long period of peace after the battle . Background . Oda Nobunaga controlled the last Shogun Ashikaga Yoshiaki from behind the scenes since commoners could not hold the position . Ashikaga tried to escape this predicament in 1573 by attacking Oda , but failed and was exiled , thus ending his shogunate . This left the army under control of Oda , although he was not shogun . When his own retainer Akechi Mitsuhide attempted to assassinate him in 1582 , Oda killed himself . This left the majority of the army in the control of his subordinate Toyotomi Hideyoshi . Since the Toyotomi clan was known to be descended from peasant stock , neither Hideyoshi nor his heir Hideyori would be recognized or accepted as shogun . Even though Toyotomi Hideyoshi unified Japan and consolidated his power following the Siege of Odawara in 1590 , his failures in his invasions of Korea significantly weakened the Toyotomi clan ' s power as well as the support of the loyalists and bureaucrats that continued to serve and support the Toyotomi clan after Hideyoshi ' s death during the second invasion . Hideyoshi ' s and his brother Hidenaga ' s presence kept the two main factions of the time , which rallied behind Ishida Mitsunari and Tokugawa Ieyasu respectively , from anything more than quarreling , but when both of them died , the conflicts were exacerbated and developed into open hostilities . With no appointed shogun over the armies , this left a power vacuum in the Japanese government . Most notably , Katō Kiyomasa and Fukushima Masanori were publicly critical of the bureaucrats , especially Ishida Mitsunari and Konishi Yukinaga . Tokugawa Ieyasu took advantage of this situation , and recruited them , redirecting the animosity to weaken the Toyotomi clan . Beginning . Tokugawa Ieyasu was no longer rivaled in terms of seniority , rank , reputation and overall influence within the Regency of the Toyotomi clan after the death of Regent Maeda Toshiie . Rumors started to spread stating that Ieyasu , at that point the only surviving ally of Oda Nobunaga , would take over Hideyoshi ' s legacy just as Nobunaga ' s was taken . This was especially evident amongst the loyalist bureaucrats , who suspected Ieyasu of agitating unrest amongst Toyotomi ' s former vassals . Later , a supposed conspiracy to assassinate Ieyasu surfaced , and many Toyotomi loyalists , including Toshiie ' s son , Toshinaga , were accused of taking part and forced to submit to Ieyasu ' s authority . However , Uesugi Kagekatsu , one of Hideyoshi ' s appointed regents , defied Ieyasu by building up his military . When Ieyasu officially condemned him and demanded that he come to Kyoto to explain himself before the Emperor , Kagekatsu ' s chief advisor , Naoe Kanetsugu responded with a counter - condemnation that mocked Ieyasu ' s abuses and violations of Hideyoshi ' s rules , in such a way that Ieyasu was infuriated . Afterwards , Ieyasu summoned the help of various supporters and led them northward to attack the Uesugi clan . Many of them were at that moment were besieging Hasedō though . Ishida Mitsunari , grasping the opportunity created by the chaos , rose up in response and created an alliance to challenge Ieyasu ' s supporters . Troop deployment . Mitsunari , in his home Sawayama Castle , met with Ōtani Yoshitsugu , Mashita Nagamori , and Ankokuji Ekei . Here , they forged the alliance , and invited Mōri Terumoto , who actually did not take part in Sekigahara , to be its head . Thus formed what came to be referred to as the Western Army . Mori seized Osaka Castle for their base of operations , since most of Tokugawa ’ s forces had vacated the area to attack Uesugi . Ishida wanted to reinforce Mori at the impregnable Osaka Castle . This would let Mitsunari control the traditional capital city of Kyoto and challenge Tokugawa ’ s power . To this end , Mitsunari ’ s forces headed for Gifu Castle in order to use it as a staging area to move on Kyoto , since it was controlled by his ally Oda Hidenobu . Back in Edo , Ieyasu received news of the situation in the Kansai region and decided to deploy his forces . Tokugawa himself commanded 30 , 000 men and his subordinates led another 40 , 000 men . This made up the bulk of what would later be called the Eastern Army . He had some former Toyotomi daimyo engage with the Western Army , while he split his troops and marched west on the Tōkaidō towards Osaka . Since Tokugawa and his army were departing from Edo , they could only take two roads , both of which converged on Gifu Castle . Tokugawa marched on Gifu while Ishida was delayed at Fushimi Castle . This fortress was a halfway point between Osaka and Kyoto and was controlled by Tokugawa ’ s ally Torii Mototada . Ishida could not risk leaving a force that could attack his rear , so he marched on it . It took him ten days to capture Fushimi , and in that time Tokugawa had taken Gifu Castle . This forced Ishida Mitsunari to retreat southward in the rain . Tired from a day ’ s march and their gunpowder wet from the rain , Ishida and his forces stopped at Sekigahara . “ Ishida deployed his troops in a strong defensive position , flanked by two streams with high ground on the opposite banks . ” His right flank was reinforced by daimyo Kobayakawa Hideaki on Mount Matsuo . On October 20 , 1600 , Tokugawa learned that Ishida had deployed his troops at Sekigahara in a defensive position . They had been following the Western Army , and benefited from considerably better weather . At dawn of the next day , Tokugawa ’ s advanced guard stumbled into Ishida ’ s army . Neither side saw each other due to the dense fog caused by the earlier rain . Both sides panicked and withdrew , but this resulted in both sides being aware of their adversary ’ s presence . Ishida held his current defensive position and Tokugawa deployed his own forces . He sent his allies ’ forces in a line to the front , and held his own troops in reserve . Around 8AM , wind blew away the fog , and both sides noticed their respective adversary ’ s positions . Last - minute orders were issued and the battle began . The battle . Initially , Ieyasu ' s eastern army had 75 , 000 men , while Mitsunari ' s western army numbered 120 , 000 . Tokugawa had also sneaked in a supply of arquebuses . Knowing that Ieyasu was heading toward Osaka , Mitsunari decided to abandon his positions and marched to Sekigahara . Even though the Western forces had tremendous tactical advantages , Ieyasu had already been in contact with many daimyo in the Western Army for months , promising them land and leniency after the battle should they switch sides . Tokugawa ’ s forces started the battle when Fukushima Masanori , the leader of the advanced guard , charged north from Tokugawa ’ s left flank along the Fuji River against the Western Army ’ s right center . The ground was still muddy from the previous day ' s rain , so the conflict there devolved into something more primal . Tokugawa then ordered attacks from his right and his center against the Western Army ’ s left in order to support Fukushima ’ s attack . This left the Western Army ’ s center unscathed , so Ishida ordered this unit under the command of Shimazu Yoshihiro to reinforce his right flank . Shimazu refused as daimyo of the day only listened to respected commanders , which Ishida was not . Fukushima ’ s attack was slowly gaining ground , but this came at the cost of exposing their flank to attack from across the Fuji River by Otani Yoshitsugu , who took advantage of this opportunity . Just past Otani ’ s forces were those of Kobayakawa Hideaki on Mount Matsuo . Kobayakawa was one of the daimyo that had been courted by Tokugawa . Even though he had agreed to defect to Ieyasu ' s side , in the actual battle he was hesitant and remained neutral . As the battle grew more intense , Ieyasu finally ordered arquebuses to fire at Kobayakawa ' s position on Mount Matsuo in order to force Kobayakawa to make his choice . At that point Kobayakawa joined the battle as a member of the Eastern Army . His forces charged Otani ' s position , which did not end well for Kobayakawa . Otani ’ s forces had dry gunpowder , so they opened fire on the turncoats , making the charge of 16 , 000 men mostly ineffective . However , he was already engaging forces under the command of Tōdō Takatora , Kyogoku Takatsugu , and Oda Yuraku when Kobayakawa charged . At this point , the buffer Otani established was outnumbered . Seeing this , Western Army generals Wakisaka Yasuharu , Ogawa Suketada , Akaza Naoyasu , and Kutsuki Mototsuna switched sides , turning the tide of battle . Fall of the Western Army . Heavily outnumbered , Otani had no choice but to retreat . This left the Western Army ’ s right flank wide open , so Fukushima and Kobayakawa began to roll up it . Thus Ishida ’ s right flank was destroyed and his center was being pushed back , so he decided to retreat . Ishida ’ s only remaining forces were on Mount Nangu . However , these forces were there for a reason . Kikkawa Hiroie was one of the commanders on the mountain . Kikkawa ' s troops formed the front lines of the Mori army , which was commanded by his cousin Mori Hidemoto . Earlier , when Hidemoto decided to attack the Tokugawa forces , Hiroie refused to comply , stating he was busy eating and asked to be left alone . This in turn prevented the Chosokabe army , which deployed behind the Mori clan , from attacking . When Ishida arrived , Kikkawa betrayed him as well . He kept the Mori army at bay , and since Ishida had no more support , he was defeated . The Western Army disintegrated afterwards , and the commanders scattered and fled . Some , like Ukita Hideie managed to escape , at least initially . Many others did not . Shima Sakon was shot and fatally wounded by a round from an arquebus and Ōtani Yoshitsugu committed suicide . Mitsunari , Yukinaga and Ekei were some of those who were captured and a few , like Mōri Terumoto and Shimazu Yoshihiro were able to return to their home provinces . Mitsunari himself would be executed . Late arrivals . Both sides had forces that did not arrive at Sekigahara in time to participate due to other battles . Ieyasu ' s son Hidetada led another group through Nakasendō . However , Hidetada ' s forces were bogged down as he attempted to besiege Sanada Masayuki ' s Ueda Castle against his father ' s direct orders . Even though the Tokugawa forces numbered some 38 , 000 , an overwhelming advantage over the Sanada ' s mere 2 , 000 , they were still unable to capture the strategist ' s well - defended position . At the same time , 15 , 000 Toyotomi troops were being held up by 500 troops under Hosokawa Yusai at Tanabe Castle in present day Maizuru , Kyoto Prefecture . Some among the 15 , 000 troops respected Hosokawa so much they intentionally slowed their pace . Due to these incidents , a large number of Tokugawa - and Toyotomi - aligned troops failed to show up in time for the battle . Had either of these armies participated in the conflict , it could have ended quite differently . Rise of the Tokugawa Shogunate . Tokugawa Ieyasu redistributed the lands and fiefs of the participants , generally rewarding those who assisted him and displacing , punishing , or exiling those who fought against him . In doing so , he gained control of many former Toyotomi territories . Tokugawa himself also became quite wealthy . Following the public execution of Ishida Mitsunari , Konishi Yukinaga and Ankokuji Ekei , the influence and reputation of the Toyotomi clan and its remaining loyalists drastically decreased . At the time , the battle was considered only an internal conflict between Toyotomi vassals . However , after Ieyasu was named Shogun in 1603 by Emperor Go - Yozei , a position that had been left vacant since the fall of the Ashikaga shogunate 27 years earlier , the battle was perceived as a more important event . In 1664 , Hayashi Gahō , Tokugawa historian and rector of Yushima Seido , summarized the consequences of the battle : " Evil - doers and bandits were vanquished and the entire realm submitted to Lord Ieyasu , praising the establishment of peace and extolling his martial virtue . That this glorious era that he founded may continue for ten thousands upon ten thousands of generations , coeval with heaven and earth . " Seeds of dissent from Sekigahara . While most clans were content with their new status , there were many clans , especially those on the western side , who became bitter about their displacement or what they saw as a dishonorable defeat or punishment . Three clans in particular did not take the aftermath of Sekigahara lightly : The descendants of these three clans would in two centuries collaborate to bring down the Tokugawa shogunate , leading to the Meiji Restoration . Other reading . Paul Davis used the following sources to compile the chapter " Sekigahara , 21 October 1600 " in " 100 Decisive Battles : From Ancient Times to the Present " " Sekigahara , 21 October 1600 . "