In The Five Rings, there is a section entitled “Becoming the Adversary”, in which Miyamoto Musashi writes that “…you should think of yourself in the place of the opponent.”
It’s an often-used trope in detective movies and TV shows that “to catch a criminal, you have to think like a criminal”. This is certainly one form of “becoming the adversary”.
However, Musashi writes specifically about this in situations when your opponent seems to be in a position of power: “…if you convince yourself that the enemy is strong, you will think it a very serious matter to attack them.” An army barricaded in a castle may seem, from outside, to hold a position of strength, but in fact they are trapped. They have limited supplies, and replenishments could be cut off at any time.
“OK,” you may think, “I’m not a detective, and I’m not laying any sieges these days. What’s this ‘becoming the adversary’ got to do with me?”