Thus we may know that there are five essentials
for victory:
(1) He will win who knows when to fight and when
not to fight.
(2) He will win who knows how to handle both superior
and inferior forces.
(3) He will win whose army is animated by the same
spirit throughout all its ranks.
(4) He will win who, prepared himself, waits to take
the enemy unprepared.
(5) He will win who has military capacity and is
not interfered with by the sovereign.

Hence the saying:

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.