These are the words of Master Sun:
There are five ways in which fire may be employed: First, soldiers may be burned when encamped. Second, supplies may be burned. Third, wagon trains may be burned. Fourth, weapons depots may be burned. Fifth, fire may be hurled into enemy formations.
We must own the means of making fire when preparing for an attack. Therefore, the materials needed for making fire must always be kept at the ready.
Certain seasons are more conducive to fire than others, and on certain days enormous fires can be started. The best time for employing fire is when the weather is dry; the best days for using fire are days when the moon is aligned with the Crossbar, the Swing, the Wall, or the Sieve [i.e. different star constellations], as these are days of rising wind.
When you attack with fire, five developments are possible:
Wind that gathers strength during the day lasts for a long time, while the wind of the night quickly fades.
A commander should know of the five developments that are possible when you attack with fire. Likewise, the movements of the stars should be constantly calculated, and there should always be a sentry watching for when the conditions are favorable for an attack with fire.
The wise commander employs fire when he attacks, but he also employs water when it can augment his strength. A flood may cut off the enemy even if it does not destroy the supplies of the enemy as a fire would.
Ill-fated is the commander who wins battles and orders attacks without employing fire or water, for he wastes both time and resources.
Thus the proverb: "The enlightened sovereign plans for the future, and the skilled commander gathers resources."
Never move your army unless you gain an advantage by doing so. Only deploy your troops if you have something to gain by doing so. Only engage in battle when the situation is critical.
A wise sovereign refrains from fielding troops with the sole purpose of gratifying his own anger. A wise commander avoids fighting battles to mend wounded pride. An angered sovereign may yet be appeased, and a prideful commander may yet find himself restored, whereas the destruction of the state cannot be reversed just as the dead cannot be brought back to life. The enlightened sovereign and the skilled commander are therefore careful not to make hasty decisions that threaten the peace and unity of the state and the army.