17. Thus we may know that there are five essentials for victory: <br>(1) He will win who knows when to fight and when not to fight.<br> (2) He will win who knows how to handle both superior and inferior forces.<br> (3) He will win whose army is animated by the same spirit throughout all its ranks.<br> (4) He will win who, prepared himself, waits to take the enemy unprepared.<br> (5) He will win who has military capacity and is not interfered with by the sovereign.<br> 18. Hence the saying: <b>If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself you will succumb in every battle.</b>