Know the enemy, know yourself
and you will meet with no danger in a hundred battles.
If you do not know the enemy but you know yourself,
then you will win and lose by turns.
If you know neither the enemy nor yourself, you will lose every battle.
Certainly.
Know your enemy, know yourself.
These words, or a variation of them,
have formed the basis of countless teachings on strategies for success in almost all walks of life,
from how to make the best business deals or lift the most trophies in sport
to the cut and thrust of domestic politics and the dark arts of international relations.
They've even been applied to dating.
And the words come from the Art of War,
a Chinese text on military strategy written more than 2,000 years ago and one of the most important works on warfare ever written.
For many, though, the text has become much more than that,
a philosophical classic, a manual even for how to overcome life's many obstacles.
But what exactly is the message of the Art of War?
And what do we know about its author, Sun Tzu, or Sun Tzu, as many English speakers say,
and how many of the politicians,
military strategists and celebrities you like to quote from it have actually read it?