After bowing again, he said, "After listening to Master's explanation, I not only know the method of defending the city, but also know the secret of building the city wall, which is really beneficial. The disciple also had questions, if someone who is good at attacking the city digs an underground tunnel under the city wall, sets fire to the pillars in the tunnel, and the tunnel collapses, and the city wall collapses in this way, and the city wall is destroyed, how should the people in the city deal with it? ”

When Mozi heard this, he praised and said, "Very good! is worthy of being the descendant of Guan Zhong, he can always find the wonderful part when looking at the problem, and he can always think of the profound position when asking questions. You're asking about a defensive method that uses tunneling to attack a city, right?

The siege method of dealing with tunneling was to build tall buildings inside the city to closely observe the enemy's situation. If the enemy has changed, building a bunker wall and accumulating earth and rocks is different from the normal situation, if you find that there is muddy muddy water around you, it is the enemy digging a tunnel. Ditches and tunnels should be dug in the city in the direction of the enemy's tunnels to prevent it. If it is not possible to accurately determine the direction of the enemy's tunnel, dig wells in the city, digging wells every five steps, close to the base of the city wall. Dig five feet deep in high places, and dig three feet deep in low places. He ordered the potter to burn a jar with a large belly and a small mouth, which could hold more than 40 buckets, to cover the mouth of the jar with thin leather and put it into the well, and to send a person with a keen sense of hearing to lie down on the mouth of the altar and listen to the sound from the ground, to find out exactly where the enemy's tunnel was, and then to dig a tunnel to fight it.

Then he ordered the potter to fire the earthen pipes, each two feet five inches long and six in size, and cut them into two pieces, and put them together in the tunnel, and the two pieces were formed into cylinders up and down. Properly coat the gaps on the outside of the cylinder with mud, and do not ignite those that have been formed into cylinders. After the cylinder is connected to the long pipe, it is necessary to coat the mud on all sides of the interface to avoid smoke leakage. Such shingles are installed on both sides of the tunnel, extending with the tunnel and pressing close to the ground. In the tile pipe is prepared with chaff and charcoal, which can not be filled and blocked, but it should be loaded all the way along the pipe, not interrupted, and at the same time should be evenly adjusted. To build a stove at the mouth of the tunnel, the shape of the stove must be similar to that of the kiln where the pottery is burned, so that it can hold seven or eight mugwort balls, and the mouth of the tile pipes on both sides is like this, and the wormwood is easy to light smoke, and the stove is equipped with four leather bellows. When the tunnels between the enemy and the enemy were about to meet, they used a weapon called 'Jiegao' to break through the layer and immediately encourage the bellows to smoke the enemy. If you can add pepper and other substances, the effect is better. Be sure to send someone who can operate the bellows extremely skillfully to use the bellows, and not let them leave the stove.

Assemble the planks, according to the height and width of the tunnel, and order the soldiers who build the tunnel to carry the puzzle forward, and make holes in the puzzle, the size of which allows the spear to pass through, and the dense intersperse, so that they can be used to rescue the enemy from the destruction of the tile pipe. Once the tunnel between the enemy and us is opened, the enemy is blocked with a puzzle, and a spear is stretched out from the hole to rescue the tile pipe to prevent the pipe from being blocked; If the pipe is blocked, pull the puzzle back a section of tile pipe to block the enemy, chisel the blocked tile pipe, so that the smoke is unblocked, and as soon as the smoke passes, it will accelerate the agitation of the bellows to smoke the enemy. At the same time, in the tunnel, it is necessary to pay attention to the sounds coming from the left and right sides, and once the situation is detected, immediately try to cut off and block the enemy's advance. If you rush into the enemy's tunnel, you will block the enemy with mud-coated firewood and prevent them from burning our puzzles. In this way, the enemy's siege by tunneling failed.

If the enemy is already under the city, the military situation is urgent, and it is necessary to beware of the enemy digging tunnels to attack the city. As soon as the enemy shows signs of digging a tunnel, he should quickly build a tunnel to confront it. If the location of the enemy's tunnel has not yet been clarified, our tunnel should be dug cautiously and not blindly attacked.

Anyone who attacks by tunneling must dig a tunnel every 20 steps, 10 feet high and 10 feet wide. When digging forward, each step is three feet lower, and ten steps deeper, and the branch road is excavated horizontally on both sides, which is called 'Yong Cave', and the height and width are also ten feet respectively.

Defeat the enemy's tunnel siege, bury two jars, the depth of the altar level with the ground, and cover the altar with wooden planks to listen to the sound from the ground. Listen for the well that the enemy is using to dig tunnels, and dig one every five steps. Each tunnel entrance is equipped with a tunnel door made of table and pine wood, and two tribulus terrestris are installed inside the door, the length of which is the same as the height of the door. Iron hoops are attached to the doors. Outside the door, a wall is built with stones, seven feet high, and a zigzag correction wall is added to the wall, and no ladders and stones are built inside the wall, and a ladder is used to go up and down. Stoves were built and bellows were installed, and the bellows were made of cowhide and agitated with levers. There is coal in the furnace, weighing forty catties; Burning charcoal is used to fuel coal, and the stove is filled with a lid to prevent the smoke from escaping. When the enemy's tunnel is about to be connected to us, according to the situation of the enemy's tunnel and the upper and lower positions of my tunnel, dig up or down respectively to open it. When encountering the enemy in a tunnel, resist rather than drive them away, you can even pretend to be defeated and wait for the fire to burn, and as soon as the fire burns, you will immediately leave the enemy and enter the cave.

Build a 'dog's den' in the tunnel, and set up doors and locks so that the dog can walk back and forth in it. A dog is placed in each tunnel, and a barking dog indicates that there is a person.

Place wormwood and firewood cut into one-foot pieces in the stove. The first stone was built into the wall of the stove, and the wooden planks were spliced together against the tunnel.

The well should be drilled close to the foundation of the city wall. Dig a well every three zhang away. It is necessary to drill wells according to the width and narrowness of the terrain, and be cautious and not careless. The foundation of the city is deep and the opening is high, so it is difficult to dig the tunnel. He dug three or four wells under the city walls, put the covered jar into the well, and put his ear to the mouth of the altar and listened to the sound from the ground. Once you have figured out exactly where the enemy's tunnel is, you can dig a tunnel from inside the castle to oppose it. When the tunnel between the enemy and us is about to be connected, we must make a punch rod with hard materials to form a spur, and the punch rod is equipped with a sharp axe, and order three brave and powerful people to use the Jie Gao to impact the soil layer of the enemy's tunnel, and once it is opened, pour more than a dozen loads of chaff, and other unclean things into the enemy tunnel. Put the personnel in an emergency ambush in the tunnel well, pile seven or eight bundles of wormwood on it, cover the mouth of the well with a large basin, do not let the fireworks come out, install bellows next to it, and quickly blow smoke into the enemy's tunnel.

Tie the wheels into 'slangs', connect them with wood, soak the hemp rope and coat it with mud to tie the wheels. Hang the wheel with an iron chain at the mouth of the tunnel where the enemy is attacking. The iron chain is three feet long, one end is tied into a ring, and one end is attached to the hook.

Make another hole, seven feet five inches high, with a horizontal width of seven feet between pillars and a longitudinal length of two feet. There is a cushion block under the pillar, and there is a roof plate at the upper end of the two pillars, which is called. The pad blocks are also padded below, and the top plate 'negative soil' should be placed horizontally. The pillar is half thick around the second circumference, and the top plate must be installed firmly, and the column and column should not intersect.

There are two stoves at the mouth of each tunnel, and the stoves must be covered with tiled roofs, and one person each of the servants and helpers should be in charge, and there must be enough water. The method of blocking the tunnel entrance is to tie two wheels into a wheel and apply mud, and let it be suspended by a rope at a distance of four or five feet in the tunnel, according to the width of the tunnel. When the enemy attacking the tunnel rushes into our ambush door, turn the wheel that hangs the wheel and put it down to block the enemy. The masonry stove can accommodate three regiments of wormwood, so that the enemy commandos can enter our ambush circle, and we are lurking on the side of the door, holding the bellows and not leaving. The short spears used in the tunnels were cast in iron, four and a half feet long, and the same size as the 'Iron Suit Theory'. When digging a foot from the mouth of the tunnel, it is necessary to tilt down to the center of the earth, and the spear used is seven feet long. Ring cables are installed in the tunnels for upper and lower traction, and two such ring cables are installed in each tunnel.

Dig a well under the city, and when the well is about to penetrate, stand on the plate, dig obliquely to the side, and move the plate to dig the other side after the chisel is finished. The Jiegao is made into two ends, and the posts are planted next to it, and the hooks are installed at both ends. Each team of 50 tunnelers was assembled, half male and half female. To build a tunnel, you need to use a conveyor tool that can hold six bamboo baskets of earth and stones, and use a rope to cover the bottom, and you can lift and pour out the soil. After the tunnel work was suspended, each tunnel was filled with a recuperation barricade, which was guarded by seven people. A large house was built to store various tools for tunneling. In order to prevent the enemy from tunneling, the wood, stone and rubble along the moat were first collected and scattered outside the city walls, and a trench was dug inside the city until the groundwater emerged. To stop the enemy when you are about to open the enemy tunnel, you need to make an iron axe, the axe and the handle are four feet long, but you don't need to build more, as long as you have enough. If the enemy digs a tunnel, I will fight the enemy with a relative tunnel.

You also need to make a four-foot-long iron hook giant, and don't make too much, just enough to use. When the tunnel is connected to the enemy, use this weapon to hook the enemy soldier. Short spears, halberds, short bows, and short arrows do not need to be made more, just enough. As soon as the friend or foe tunnels are connected, the person who fights the tunnel can use them to fight the enemy. In the tunnel, you can also use a weapon called the 'Golden Sword', which is only five feet long and has a hole for the handle, and is made of wood, and the part of the hand on the wooden handle is carved with shallow grooves and tooth patterns.

Then prepare some large tile altars with a capacity of more than 30 buckets, and bury them in the wells, one every three zhang, to listen to the sound of the enemy digging tunnels. Excavate tunnels, eight feet high and eight feet wide, properly erect pillars, and place stoves, cowhide bellows, and tile bowls, etc., and each tunnel is equipped with two sets. The stove is filled with herbs, wormwood, etc., and as soon as the tunnel between the enemy and us is opened, the smoke will immediately burn to smoke the enemy.

Axes made of metal, with wooden handles three feet long, four for each tunnel. To prepare bamboo cages for holding soil, 40 should be prepared for each tunnel, and four hoes and so on. Equipped with axes, saws, chisels, hoes and other tools, the number is only enough to use not too much. Equipped with large scissors, four per tunnel. He made a medium-sized shield, ten and a half feet high and four feet wide. Prepare large panels that are placed horizontally in the tunnel to block the enemy. Then prepare the straw and hemp stems, don't be greedy, just enough to use for lighting. They were also to be equipped with a medicinal liquor called a medicinal liquor, which was used by the enemy to protect the eyes of their soldiers. When using smoke to attack, it is inevitable that the smoke will choke, and then our soldiers can use 'liquor' to heal their eyes, and as soon as the wounds on the eyes are removed, our soldiers will quickly dig tunnels in all directions. Put the pot with the 'liquor' in the tunnel, the large basin should not be less than four buckets of capacity, if the smoke is smoked, look down at the 'liquor' in the basin, so as to protect the eyes. ”

He bowed twice and then said, "Master, if the enemy is so strong that he climbs our wall, he will behead those who are behind him on the spot, and at the same time dig a trench under the city, build a mountain of earth, and dig a tunnel under the city. The enemy soldiers in front of them are climbing more and more, and the bows and arrows behind are shooting hard, how to deal with this situation? ”

Mozi replied, "Are you asking about a defensive strategy to deal with the enemy who climbs the city like an ant?" Relying on the strength of the crowd and driving the soldiers to forcibly attack the city like ants is just an irrational move by the enemy general in anger and urgency, the defender only needs to build temporary battlements, condescendingly shoot at the enemy who climbs the city, throw them at the enemy with 'technical machines', and pull out the enemy's climbing equipment, use torches and boiling water to subdue the enemy soldiers under the city, cover the enemy from the bottom of the city with lit war equipment called 'thorn', and hit the enemy head like rain of sand and stones, so that the forced siege method of climbing the city wall like an ant fails.

In order to prevent the enemy from climbing the city like ants and attacking the city, they could make a suspension pulley, which was made of two inches thick planks, three feet wide at the front and back, five feet wide on both sides, and five feet high, and also made a suspension block that could slide up and down, and the wheels used were one foot six inches in diameter, and a soldier was sent to stand in the carriage with a spear, the spear was two feet and four feet long, and both ends were made into blades. Attach iron chains to the beams of the upper part of the suspension pulley, attach the rollers, and send four strong and powerful soldiers to turn the wheels so that the people will rise or fall rapidly with the trunk without stopping. Such hoverplanes are placed every twenty paces in a section of the area, and every six paces in the area under enemy attack.

The beams are made of wood, tied with hemp ropes, soaked in muddy water, and equipped with iron chains that hook the rings at both ends. If the enemy climbs the city like an ant and attacks hard, ignite the 'sting' to cover the enemy from the top down. In addition, oil, sand and ash can be used to rescue and siege cities.

Equipped with two wheels, the distance between the two axles is longer, fixed with a '園', and the two ends are fused to make the two wheel bundles one, and mud is applied everywhere, and flammable materials such as elm branches and hemp stems are stuffed inside, and thorns are placed on both sides. If the enemy arrives in a group, light the 'Chuan Yu', cut the rope on it to make it roll, and order the warriors to use the soup to open the way to counterattack the enemy. As soon as the city wall is damaged, people should be immediately sent to quickly fill it up and repair it.

Sharp wooden stakes are planted in the outer wall of the city, five feet long, more than one and a half feet long, and the ends are sharpened, and five rows are buried, with a row spacing of three feet, and three feet deep, and they are to be buried like dogs' teeth. It is five feet long and ten feet wide. The 'spur' is two feet long and six inches wide, and the rope is two feet long. The vertebrae are six feet long, and the head is one foot and five inches long. The axe should be six feet long, and the edge of the axe must be sharp. 'A', one foot two feet wide, one foot six feet long, hanging four inches from the front beam. The two ends should be about a foot above each other, but not like fish scales. Tie a large rope in the middle of the rear beam, two feet six feet long. If there is a place that is not sealed, it should be stuffed with a plate, and it should be exposed to the sun more to make it dry, and the 'thorn' should be made into a grille to allow air circulation. Where the walls of the city are not too strong and are afraid of collapsing, wooden stakes should be planted in advance, one every ten feet. If the wall of the city fell, he raised a stake, pressed a crossbar on the stake, eight feet long and seven inches wide, and a foot high on the side, and hammered down the stake, and then nailed it with a horse nail.

Hooks, wooden buildings, and rolling stones must be prepared. The 'thorn' should be hung on the inner side of the pillar, not on the outer side of the pillar. Then arrange the 'squeaphyrd', bury it four feet, expose the ground to a height of ten feet, the length of the wood is alternate, the cloth is staggered, the head is sharpened, and the surrounding area is coated with thick mud. Make a row stack and hang the roasted thorns. Build a building in the corner of the city, and the building should be multi-storey. Prepare soil, five steps in a pile, each pile is not less than 20 cages.