During the 1500s Japan was in Civil War with local warlords seeking control of the country. Imagawa Yoshimoto a leading warlord in the Tōkaidō Region of Japan, led 25,000 men to march on Kyoto. On the march they entered Oda territories belonging to the much weaker warlord Oda Nobunaga.
Imagawa Yoshimoto took the border fortresses of Washizu and Marune before setting up camp in the wooded gorge known as Dengaku-Hazama. Oda’s scouts reported all of this to Oda who then moved his own forces of 2000-3000 men into a temple called Zebshio-ji.
Oda Nobunaga’s force was heavily outnumbered and his own generals urged him to surrender. Oda however had a reputation for being reckless and unpredictable even thought of by some as being mentally unstable, he ignored the advice from his generals instead ordering a dummy army be constructed at Zensho-Ji with a large number of banners to give the impression this was to be the location of his main force.
Meanwhile Oda ordered an attack and led his main force of 2000 men through the forest undetected to the rear of the Imagawa Army camped at Dengaku-Hazama. The Imagawa samurai were celebrating their recent victories at camp and did not expect and attack. A thunderstorm that took place that night shielded Oda’s men’s advance.
As soon as the storm passed, Oda’s men charged into the camp onto the drunk and unprepared army who lost all discipline with large numbers fleeing from their attackers. They left the commander’s tent largely undefended and the Oda warriors closed in. Yoshimoto unaware of what was happening heard the noise and came outside to order his men to quit their drunken activities and return to their posts. By the time he realised that the samurai in front of him were not his own it was too late to organise a defence. Yoshimoto was attacked and although deflected their initial attacks was killed by two of Oda’s samurai Mori Shinsuke and Hattori Koheita.
With Imagawa Yoshimoto dead and only two senior officers left alive, the remaining Imagawa force joined Oda’s army. Soon after the Imagawa faction was no more and Oda Nobunaga was at the front of military power.
The Blood of History 