Become an energy to know the enemy

Sword master, Musashi Miyamoto wrote:
"Become an enemy to know the enemy"
It is very important to understand the situation, psychology and skills of the opponent in the battle.
To know the enemy, first become the enemy.
I think it is a word that expresses the necessity of the relativity of things and the power to look down at battle.
Humans have a fighting instinct, but at the same time a synchronizing instinct.
With a balance between the two, with a spirit of "harmony" in the battlefield.
And always ready for both life and death 
​A wonderful philosophy that lived in the last minute situation of the Civil war era