Battle of Komaki and Nagakute The was a series of battles in 1584 between the forces of Hashiba Hideyoshi ( who would become Toyotomi Hideyoshi in 1586 ) and the forces of Oda Nobukatsu and Tokugawa Ieyasu . Hideyoshi and Ieyasu had both served Oda Nobunaga and had not previously come into conflict ; this would in fact be their only period of enmity . Although this episode of history is most commonly known by the two largest and most important battles , the event is also sometimes referred to as the Komaki Campaign ( 小牧の役 " Komaki no Eki " ) . Background . In 1583 , at the Battle of Shizugatake , Hideyoshi supported Nobukatsu , the second son of Oda Nobunaga , and defeated Shibata Katsuie , who supported Nobunaga ' s third son , Nobutaka . After winning the battle , Hideyoshi invited Nobukatsu and other generals to his residence at Osaka Castle , which he had just completed that same year . The meaning of such an invitation was for all the men to pay homage to Hideyoshi , which would reverse the roles between Hideyoshi and Nobukatsu . Therefore , Nobukatsu broke his bonds to Hideyoshi and did not go to Osaka Castle . Hideyoshi offered reconciliation to three of Nobukatsu ' s chief retainers ( Tsugawa Yoshifuyu , Okada Shigetaka and Azai Nagatoki ) , which led to rumors that they were all in support of Hideyoshi . This in turn lead Nobukatsu to become suspicious of the three men , whom he ordered executed on the sixth day of the third month . These actions gave Hideyoshi the justification for attacking Nobukatsu and , as a result , Nobukatsu asked Ieyasu for auxiliary forces . The next day , when Ieyasu sent his forces out to battle , it became a battle between Hideyoshi and Ieyasu . Order of Events . The first of these battles was fought around Mount Komaki and gave rise to the name " Battle of Komaki . " The rest of the battles took place around Nagakute , giving rise to the modern - day names for the conflict . Battle of Haguro . On the thirteenth day of the third month , Ieyasu arrived at Kiyosu Castle . On that same day , warriors of the Oda clan ' s vassals who were led by Ikeda Tsuneoki switched to the side of Hideyoshi and took over Inuyama Castle , which had originally been built by Oda Nobunaga . Ieyasu was upset upon hearing this news and rushed to Inuyama Castle , arriving two days later . At the same time , Mori Nagayoshi ( brother of Mori Ranmaru , who died at the Incident at Honnō - ji with Nobunaga ) began his attempt for the Kiyosu Castle . Despite fierce arquebus fire from Mori ' s men , Sakai Tadatsugu succeeded at flanking and attacking Mori in the rear . Mori fled , having suffered 300 casualties . On the sixteenth day of the month , forces called to support Inuyama Castle arrived in Haguro . Ieyasu , however , had already known of these plans and had Sakai Tadatsugu and Sakakibara Yasumasa move 5 , 000 troops to Haguro that same evening . Early the following morning , Tadatsugu ' s troops launched a surprise attack on Nagayoshi , whose troops barely escaped after the onslaught . On the eighteenth , without fear of raids from enemies , Ieyasu took over Inuyama Castle and finished the defenses that had first been built up by Hideyoshi . Mission to Mikawa . Hideyoshi and his troops left his fortifications at Osaka Castle on the 21st day of the month , arriving at Inuyama Castle on the 27th day , and in Gakuden ( present - day Inuyama ) on the fifth day of the following month . Ieyasu , between entering Komakiyama Castle and arriving in Gakuden , stayed away from battle , except for a few smaller skirmishes here and there . Hideyoshi was lulled into complacency by this situation , aided by Tsuneoki , who said to him , " Ieyasu is now in Komakiyama Castle . He is away from his main base in Okazaki and if we were to move our arms against him , we will certainly win . " The ambitious Hideyoshi decided to set out for Mikawa , along with the support of Nagayoshi ( who had regained his reputation at the Battle of Haguro ) , Tsuneoki ( who was embarrassed by his daughter ' s marriage ) and the young Hidetsugu ( 17 years old at the time ) . Toyotomi Hidetsugu was able to amass 8 , 000 men , which were supported by Hori Hidemasa ' s 3 , 000 men , Mori Nagayoshi ' s 3 , 000 men and Tsuneoki ' s 6 , 000 men . On the following day , they all set out for Mikawa . Battle of Iwasaki Castle . The Battle of Iwasaki Castle was fought between the forces of Niwa Ujishige and Ikeda Tsuneoki . Though it was just part of overall Battle of Komaki and Nagakute , it played an important role in the outcome . On the seventh day of the month , Ieyasu learned of Hidetsugu ' s encampment at Shinogi ( modern - day Kasugai ) through the information provided by farmers in Iga Province . He entered into Obata Castle ( Moriyama - ku , Nagoya ) the following day and chose to pitch camp for the evening . Early the next morning , he sent both the Niwa clan and the forces of Sakakibara Yasumasa to chase after Hidetsugu , and followed shortly thereafter with his own . Hidetsugu resumed his march on the eighth after hearing of Ieyasu ' s entrance to Obata Castle , but on the next morning , the situation changed very rapidly . Ikeda Tsuneoki led the attack of Iwasaki Castle ( modern - day Nisshin ) and was promptly shot off of his horse . Embarrassed by his fall , Tsuneoki forgot about the hit - and - run tactics and started a full assault on the castle . Though the defenders fought well , the castle fell . During the battle , Mori Nagayoshi , Hori Hidemasa and Hidetsugu all rested their forces at the modern - day cities of Owariasahi , Nagakute and Nisshin , waiting for the oncoming forces , as Ieyasu was closing in on them . Battle of Hakusanmori . At the time that Ikeda Tsuneoki was shot and fell from his horse at Iwasaki Castle , Toyotomi Hidetsugu moved his forces to Hakusanmori ( present - day Owariasahi ) to rest , but it was there that he met the forces of Ieyasu and Sakakibara Yasumasu . Hidetsugu ' s forces were pretty much destroyed by Ieyasu ' s surprise attack . Hidetsugu himself was knocked from his horse , but was able to get another horse and escape . It was at this battle that many members of the Kinoshita clan ( including Sukehisa , the father of Hideyoshi ' s wife , Nene ) died . Battle of Hinokigane . Following the battle of Hakusanmori , Tokugawa fortified Mt . Komaki , creating a stalemate there . Thus , Ikeda Nobuteru , one of Toyotomi Hideyoshi ' s chief commanders , decided to begin raids through neighboring Mikawa Province with an army numbering 20 , 000 . Tokugawa expected this and led a force to follow Hideyoshi ' s . Mizuno Tadashige led Tokugawa ' s rearguard against Ikeda ' s force and the noise of the battle alerted Hori Hidemasa , the head of one of Hideyoshi ' s divisions . Hori Hidemasa led his men to the defense of his comrades , taking up position in the village of Nagakute . He held off the initial Tokugawa attacks , but was forced to withdraw as the main body of the Tokugawa army , numbering some 9000 warriors , arrived . Battle of Nagakute . The battle proper began as Ikeda ' s men opened fire with their arquebus es and then charged the Ii clan ' s divisions of the Tokugawa force . Mori Nagayoshi , another of Hideyoshi ' s commanders , waited until Tokugawa moved in to support the Ii , so that he could flank them . However , Tokugawa charged forward , rather than swinging around , and avoided the flanking maneuver . Mori Nagayoshi was shot off his horse , which demoralized Ikeda ' s force . Ikeda ' s head was taken soon afterwards and , despite Hideyoshi ' s arrival with reinforcements , Ieyasu decided to withdraw , unwilling to risk further casualties , and returned to Komaki . Aftermath . When news of the loss at the Battle of Hakusanmori arrived in the afternoon , the 20 , 000 troops of Hideyoshi rushed to Ryūsen - ji , near the battle site . Later that evening , when they heard that Ieyasu was staying at Obata Castle , they decided to assault it the next morning ; however , during that time , Ieyasu had left Obata Castle , went to Komakiyama Castle and finally returned to Kiyosu Castle . Hideyoshi heard the news of Ieyasu ' s departure shortly thereafter and , on the tenth day of the fourth month , left Gakuden ; he arrived back at Osaka castle on the first day of the following month . On the 16th day of the sixth month , Takigawa Kazumasu attacked Ieyasu ' s Kanie Castle , but was driven back . As a result , Kazumasu had his responsibilities taken from him and removed from Ieyasu ' s group . On the ninth day of the ninth month , Sassa Narimasa , at the behest of Ieyasu , attacked Suemori Castle in Noto Province , forcing out its resident , Maeda Toshiie . Names for the Battle . During the Edo period , the public records of the Tokugawa clan and the shogunate refer to these battles as Battle of Komaki ( 小牧陣 " Komaki no Jin " ) . However , there are also documents that refer to it as the Battle of Iwasakiguchi ( 岩崎口の戦い " Iwasakiguchi no Tatakai " ) . There are places where the fighting in Nagakute is called the Battle of Nagakute ( 長久手合戦 " Nagakute Gassen " ) , but the two battles have generally been merged into one . Many other names have also been used to describe these battles , some of which separate the two , while the others keep them together . During the Meiji Restoration , the various Japanese words for battles , campaigns , etc . , were mostly unified , leading to it sometimes being called the Komaki and Nagakute Campaign ( 小牧 ・ 長久手の役 " Komaki - Nagakute no Eki " ) . Through all of this , though , " Battle of Komaki and Nagakute " has come to be the accepted name .