The Army on the March

Sunzi said: In general, when deploying troops and observing the enemy, one should note the following: When passing through mountainous terrain, advance along valleys; encamp on high ground facing the sun. If the enemy occupies high ground, do not attack them uphill. This is the principle for deploying troops in mountainous terrain. After crossing rivers, you must move far away from the river before encamping. If the enemy crosses a river to attack, do not meet them in the water; instead, let them get halfway across before striking, which is advantageous. If you wish to engage the enemy in battle, do not position yourself near the water’s edge facing them; encamp on high ground facing the sun and do not camp facing upstream. This is the principle for deploying troops in riverine terrain. When passing through salt marshes and swampland, move through quickly and do not linger. If you must engage the enemy in salt marshes or swampland, be sure to stay near water and grass, and keep your back to a grove of trees. This is the principle for deploying troops in salt marsh terrain. On level plains, occupy open and flat ground, with your main force positioned on high ground, low in front and high in the rear. This is the principle for deploying troops on plains terrain. The advantages derived from these four methods of deployment are the reasons why the Yellow Emperor was able to defeat the tribal leaders of the four directions.

In general, when encamping, armies prefer high ground and dislike low-lying areas, value sunny positions and disdain damp, shady ones. Encamping in places that are convenient for living and on solid ground prevents the army from suffering various diseases; this is called being assured of victory. On hills and embankments, you must encamp on the sunny side, with your main force backed against them. These measures are all advantageous for military operations and represent assistance from the terrain. When rain falls upstream and foam drifts down, if you wish to ford the river, wait until the water has stabilized.

Wherever the terrain features “sheer ravines,” “natural wells,” “natural prisons,” “natural nets,” “natural traps,” or “natural fissures,” you must quickly move away and not approach them. We should keep our distance from them, drawing the enemy close to them; we should face them, making the enemy turn their backs to them. When there are dangerous defiles, marshlands with reeds, dense forests, or thick undergrowth alongside the army’s route, you must carefully and repeatedly reconnoiter, for these are places where ambushes and spies may lie.

If the enemy is near but remains still, they are relying on the advantage of the terrain. If the enemy is far away but issues a challenge, they wish to lure our forces forward.

If the enemy encamps on level ground, it is because they have some advantage.

When many trees move, it means the enemy is approaching. When there are many obstacles in the grass, it is a ruse laid by the enemy.

When birds startle and fly up, there is an ambush. When wild animals flee in terror, it indicates a large-scale enemy attack.

When dust rises high and sharp, it signals chariots coming. When dust is low and broad, it signals infantry coming.

When dust is scattered and thin, the enemy is gathering firewood. When dust is sparse and comes and goes, the enemy is setting up camp.

If the enemy’s envoys speak humbly but their war preparations increase, they are about to attack. If their words are harsh and they assume an offensive posture, they are about to retreat.

If light chariots are sent out first and deployed on the flanks, they are forming a battle array. If they seek peace without prior agreement, they are plotting. If they rush about and deploy their chariots in formation, they are expecting to engage us. If they advance halfway and then retreat, they are luring us on.

If enemy soldiers lean on their weapons while standing, they are hungry. If those drawing water drink first, they are thirsty. If they see an advantage but do not advance, they are exhausted.

If birds gather on the enemy’s camp, it means the camp is empty. If there are cries at night, it indicates fear.

If the army is in disorder, the general lacks authority. If the banners and flags are moving about, the ranks are confused. If the officers are angry, the troops are weary.

If they feed grain to horses and kill cattle for meat, do not hang up their cooking pots, and the soldiers do not return to their tents, they are desperate and have no way out.

If the officers speak to the troops in a subdued and hesitant manner, the general has lost the people’s hearts.

If rewards are frequently given, the situation is difficult. If punishments are frequently inflicted, the situation is dire.

If the general is initially harsh and later fears his men, he is utterly incompetent. If the enemy sends envoys to apologize humbly, they wish to cease hostilities.

If the enemy advances aggressively but does not join battle for a long time, and does not withdraw, you must carefully observe them.

Having more troops is not necessarily better; as long as you do not advance recklessly, you can concentrate your strength, assess the enemy, and defeat them. Only those who lack deep planning and are rash will surely be captured by the enemy.

If soldiers are not yet attached and devoted to you, punishing them will cause resentment, and resentment makes them difficult to use. If soldiers are already attached and devoted, but discipline is not enforced, they cannot be used in battle. Therefore, employ humane measures to unite them and strict military discipline to regulate them; this will surely lead to victory. If orders are consistently enforced and the troops are educated, they will obey. If orders are not consistently enforced and the troops are not educated, they will not obey. When orders are consistently carried out, it means the general and his soldiers are in harmony.