Today we, in the United States, tend to regard Sun Tzu's maxim "If you know the enemy and know yourself, you need not fear the result of a hundred battles" as being about the physical capabilities, C4ISR (Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance), weapons, and warfighting capability of our own forces and those of the adversary. Given the rest of The Art of War, and its focus on preventing such actions, it is likely that Sun Tzu was referring much more to the understanding of the psyche than to the material aspects of warfare.