The Key Points

Here are the four key points what I think made Nobunaga's victory possible in my opinion.

• The rainstorm/thunderstorm
• The intelligence from Yanada Masatsuna
• Nobunaga's small army
• Okehazama itself

I wrote in great detail on the four key points in my book on pages 99-106.

Wataru Kajino's Jimoto no Karo ga Kataru Okehazama Kassen Shimatsu ki listed seven key points as well (pp. 45-48).

• Fighting spirit
• Tactics
• Intelligence
• Quality of troops
• Geography
• Weather
• Others such as charisma

As for myself, The rain and the Yanada Masatsuna's intelligence are the top two. The weather was hot, sticky, and miserable. The heat forced Yoshimoto's army to stop to rest. Then the rain/thunderstorm started, but it was down right deadly. There was lighting which forced the army to look for cover. Owada Tetsuo has noted that the rain was one of the deciding factors of the battle. The Imagawa main army could not spot the Oda due to negligence or the dark skies. When Nobunaga gave the order to attack, the Imagawa army was not prepared for it.

Yanada Masatsuna's intelligence was also a game changer. Once Nobunaga received the information without the bureaucratic chain of command, he went straight for the kill. It was like a shark smelling blood in the water. Both Nobunaga and Masatsuna knew the Okehazama geography very well. After the battle, Nobunaga rewarded Masatsuna with Kustukake Castle and cash.

Nobunaga knew the value of human intelligence and he was successful using the resources he had. Okehazama changed warfare from military exploitation to the age of human intelligence in my opinion.

Nobunaga no tame!