Which idea do you think is the most effective strategy in Sun Tzu's Art of War?

Only knowing that our army can fight, but not knowing that the enemy cannot fight, the possibility of winning is only half; Only knowing that the enemy can fight, but not knowing that our army cannot fight, the possibility of winning is only half; If WE KNOW THAT THE ENEMY CAN fight AND WE KNOW that our army can fight, but we do not know the terrain conditions, we have only half a chance to win.