There is a saying in Asian classical battle principle by Sun Tzu (c.
6th century BC) who was a Chinese General, military strategist, and author of The Art of War, an immensely influential ancient Chinese book on military strategy; said, .
Know your enemy and know yourself, find naught in fear for 100 battles.
Know yourself but not your enemy, find level of loss and victory.
Know thy enemy but not yourself, wallow in defeat every time.
(知彼知己,百戰.