You're right... My mistake... It's a bad mistake also because I know Chinese and I read the original version in classical Chinese. It's Sun Zi Bing Fa - The Military Rules. The emphasys is not only know yourself but know both yourself and your enemy. Sunzi said something like (quote from my memory): If you know neither yourself nor the enemy, you are bound to loose. If you know the enemy but dont' know yourself you have half the chances. If you know both yourself and the enemy than you have all it takes to win.