The art of war

Sun tzu's famous quote in mandarin:

知已知彼, 百战百胜.

This is the quotation in english (I personally think that the translation is not completed):

If you know the enemy and know yourself you need not fear the results of a hundred battles. - Sun Tzu

It would be better to interpret as:
Know yourself and your foe, and you will achieve victory in every war.