Master Sun says when attacking by fire, there are five ways to do it, burning men, supplies, equipment, warehouses, and lines of communication. You must have the means and the material. Certain seasons and days are best for lighting fires. Ideally, strike when it is hot and dry. The best days are when the moon is in Sagittarius, Pegasus, Crater, and Corvus. They are the four constellations of rising wind.
Sun describes the Way of warfare by fire. First the general must have the material, then he can pick the target. He must pay close attention to the climate and conditions, ensuring that the fire will continue to burn and ravage the enemy position. There are certain times of year that are most favorable for fire—that is, when it is hot and windy.
The are five changes to adapt to. If an enemy camp breaks out with fire, attack immediately. If the enemy remains calm, do not attack, but watch how the fire spreads and strike if an opportunity arises. If you can start a fire in the enemy camp, do it when the time is right. Always be upwind when starting a fire. Winds that start in the day last a long time. Night winds die out quickly. Know these changes and be vigilant.
Fire moves quickly. So must the general if he is to make the most of the opportunity. He must stay alert and move when there is an advantage, while ensuring his own men will be safe. Sun advises a day attack, as the winds are favorable and will help to maximize damage in the enemy camp.
Fire is a massive help in war. Water can be a big help too. It isolates but does not kill entirely. Not following through on an opportunity is a great waste. Thus it is said, good rulers think deeply, good generals follow through. Only move for gain or victory, and fight only in a crisis. Rulers must never mobilize out of anger, and generals must not fight out of spite. Move for gain; halt if there is none.
Fire is more destructive than water, but the latter can be a strategic asset too. An efficient general makes the most of every opportunity and uses it to its full advantage. He should be focused on victory, and only act to draw closer to that goal. Fighting is a last resort, as it drains resources and has great potential for harm. Both the ruler and the general must order battle only when it is truly necessary.
Anger and spite can subside to joy, but once a nation or men are destroyed, they cannot be rebuilt. Rulers must be prudent and generals cautious. This is the Way to preserve peace and keep men whole.
If the ruler or general act rashly in an emotional rage, the damage they cause cannot be undone. Instead, they should be wise and patient, choosing the best course of action for their nation.