Battle of Okehazama The took place in June 1560 . In this battle , Oda Nobunaga defeated Imagawa Yoshimoto and established himself as one of the front - running warlords in the Sengoku period . Background . In May or June 1560 , Imagawa Yoshimoto , with an army of about 25 , 000 men , set forth on a march to Kyoto . Entering the Oda territories in Owari Province , he first took the border fortresses of Washizu and Marune before setting up camp in a wooded gorge known as Dengaku - hazama . This was all reported to Oda Nobunaga by his scouts and , in response , Nobunaga then led his own forces into position at a temple called Zenshōji , a short distance away , on the other side of the Tōkaidō . Had Nobunaga decided on a frontal assault , the battle would have been deceptively easy to predict ; his army was outnumbered ten to one by the Imagawa forces . A frontal assault would be suicidal and an attempt to hold out at Zenshō - ji would only last a few days . Because of the odds against their side , some of Nobunaga ' s advisers even suggested a surrender . Nobunaga , however , decided to launch a surprise attack on the Imagawa camp . When he made his decision , he gave this speech : " Imagawa has 40 , 000 men marching toward this place ? I don ' t believe that . He ' only ' has 25 , 000 soldiers . Yes , that is still too many . So , Sado , you want me to surrender . What if we do surrender ? Will you get content with losing your life that way ? Or what if we hold on like Katsuie wants me to ? What if we stay here in this castle , lock it up , and wait until the Imagawas lose appetite and stop the siege and go home ? We will be able to prolong our lives for five or ten days , and what we cannot defend will still be undefendable . We are at the bottom of the pit , you know . And our fate is interesting . Of course the misery is too great , too . But this is how I see it : this is a chance in a lifetime . I can ' t afford to miss this . Do you really want to spend your entire lives praying for longevity ? We were born in order to die ! Whoever is with me , come to the battlefield tomorrow morning . Whoever is not , just stay wherever you are and watch me win it ! " Battle . Nobunaga left a small force at the temple with a large number of banners , to give the impression that this was the location of his main force . Meanwhile , Oda ' s main force ( about 1 , 500 men ) moved through the forest undetected to the rear of the Imagawa army . The Imagawa samurai did not expect an attack , and that afternoon was very hot . The histories say that the Imagawa were celebrating their recent victories with song , dance , and sake . An afternoon rainstorm further aided Oda ' s soldiers who arrived at the Imagawa camp just as the rains came down ( this was the afternoon of 12 June ) . When the storm passed , Nobunaga ' s men poured into the camp from the north , and the Imagawa warriors lost all discipline and fled from the attackers . This left their commander ' s tent undefended , and the Oda warriors closed in rapidly . Imagawa Yoshimoto , unaware of what had transpired , heard the noise and emerged from his tent shouting at his men to quit their drunken revelry and return to their posts . By the time he realized , moments later , that the samurai before him were not his own , it was far too late . He deflected one samurai ' s spear thrust , but was beheaded by another . Aftermath . With their leader dead , and all but two of the senior officers killed , the remaining Imagawa officers joined Oda ' s army . Soon the Imagawa faction was no more and Oda Nobunaga was famous as his victory was hailed by many in Japan as miraculous . The most important of the samurai lords who joined Oda after this battle was Tokugawa Ieyasu from Mikawa Province . Ieyasu would remain a loyal ally of Nobunaga from this time until the latter ' s death . Legacy . In 1937 , Japan ' s Ministry of Education designated the battlefield , Okehazama Kosenjo , a national historical site . Located at Minamiyakata , Sakae - cho , Toyoake City , the site hosts The Shichikokuhyo , or Seven Granite Pillars , with each pillar representing Yoshimoto ' s seven warlords . The first of the pillars bears the words , " Imagawa Yoshimoto was killed here . " The battlefield is now a park .