Okehazama Battlefield Landmark Toyoake City Location
In my Okehazama book (both editions) I have laid out four key points to the Battle of Okehazama.
- Yanada Masatsuna's intelligence
- Small force
- Okehazama itself
Yanada Masatsuna's intelligence changed Sengoku warfare. He gave the key data where the Imagawa camp location to Nobunaga. Nobunaga knew he had to act quickly to the information. It changed everything. Nobunaga knew he had a chance to destroy the Imagawa in once punch. Okehazama went to the age of military exploitation, to the age of intelligence. Yanada was rewarded with Kutsukake Castle and cash for his service.
The small force was less detectable and provided just enough cover for a surprise attack. His earlier victories with a small army in the Owari unification process helped. He was outnumbered as well in the Battle of Moribe in 1561. More important, Nobunaga did not and could not receive any allied support. He was all on his own. The Saito/Oda allaince was broken in 1556 with the death of Saito Dosan. A larger army would have been easily spotted.
Okehazama itself. Yoshimoto could have continued to march to Odaka without the break. Sure, the weather was hot and sticky. Success was so fast for the Imagawa, Yoshimoto was very confident Nobunaga would fold by the next day. He was overconfident. Ieyasu was waiting for the arrival of Yoshimoto at Odaka Castle which never came. By resting at Okehazama, all three things occurred, thunderstorm, Yanada's intelligence, small army, and a recipe for disaster.
This is only a general explanation. The second edition goes into much detail.
Update: The second edition should be available by late May at the earliest. Made the final corrections before the publisher sent the manuscript to the printer.
Nobunaga no tame!