Hidetada Akita, a wealthy family whose loyalty was not very high, decisively raised the anti-flag under the lobbying of Hojo Phantom An!

He believes that the content of the "Nagao Samurai Law" has greatly harmed his direct interests. For example, what to cancel the checkpoint and so on, and you can't even collect tolls in the future, can you bear it? The answer is, of course, no!

"Lord, if the family doesn't look back, it's too late!" A retainer was still admonishing him not to get lost.

"The Hojo family can defeat an army of nearly 100,000, what can they do with the strength of the Nagao family? It's better to ...... it early" Hidetada stopped as soon as his words came to his lips, because at this time, he was speechless after seeing the vanguard of the Nagao family, the 500 cavalry of the Kakizaki Keijia and the 1,500 ashigaru.

It's only been a few days? Just three days! The Nagao family has sent out a crusade army! Hidetada finally understood why Hojo Phantaka didn't say that the Hojo Army would send reinforcements to help him defend the castle. Even the blank check said that they would send troops to Echigo after the Hojo family captured Kawagoe Castle. It's like the earth will always be destroyed, in a few thousand years.

Soon, before half a pillar of incense was done, the army of the Nagao family, a total of 15,000 troops, was concentrated under Zhaotian Castle. Compared to the faces of the people of the Shoda family in Zhaotian City, the atmosphere of the Longtail Army's main formation was very angry. They all scrambled to be the first to take on the role.

"Jinghu Gong, such retainers actually support the Hojo family! I ordered him to pay for what he had done, and to die for the surrender of the city or the capture of the city! When Uesugi learned of Echigo's large-scale military requisition, he came to help with the 2,000 troops of Nagao Masaki, who had stayed behind.

"What the Constitution said is extremely true, but killing him will not delay the invasion of the Hojo family and the Takeda family." Did Asadachi think Uesugi Kenmasa was in too much of a hurry?

"Then let's take the city." The girl said cold-bloodedly, ready to start commanding the siege.

"Slow, it's best to exchange the smallest casualties for the greatest victory." Chaoding thought of the tunnel blasting that had occurred during the First World War, and it was best to use it for this now. Moreover, Akita Hidetada's army was less than 3,000, and it was not enough to defend the city, so it could not be stopped at all.

Tunnel blasting is also a blasting carried out to destroy the enemy's solid targets on the ground or underground, and secretly digging tunnels below or near them. It is a kind of attacking and blasting. In China, it was formerly known as tunnel blasting. In offensive combat, when time, geological and other conditions permit, it is used to destroy targets that are not easy to destroy by artillery fire and difficult to reach on the ground. It can also be used for anti-pit blasting when defending. The pit used for blasting is generally 1×1.5 meters in cross-section. The mouth of the pit is usually selected on the hidden terrain as close to the target as possible to reduce the amount of work. The operation should be carried out in secret, and attention should be paid to camouflage and prevent the enemy from destroying the tunnel. After the advent of gunpowder, the armies of some countries used tunnel blasting in fortified operations.

This method was used, for example, when the Turks besieged Constantinople in 1453 and Kazan in 1552 when the Russians besieged Kazan. In May 1948, the Chinese People's Liberation Army successfully excavated two tunnels during the famous Battle of Linfen. A tunnel is 117 meters long and contains 6,200 kilograms; The other pit is 115 meters long and has a capacity of 2,500 kg and 500 kg. After the detonation, the city wall was blown open with two gaps about 34 meters wide at the lower opening, opening the way for the siege troops to attack Linfen City.

In modern warfare, the necessity and possibility of using tunnel blasting in offensive battles have been greatly reduced due to the advent of weapons of mass destruction and the increase in the firepower of artillery and aviation, as well as the fact that the course of the battle has been greatly shortened and the situation is changeable.

The most famous tunnel blasting is the British tunnel blasting on the Western Front during World War I.

In the early hours of June 7, 1917, during the First World War, a series of huge explosions rang out in the mountains of Ipremeson, Belgium. With the sound of explosions, the German fortifications in the Mason Mountains crumbled, weapons and equipment flew into the sky, and German officers and soldiers flew flesh and blood...... This is known as the most amazing tunnel blasting in the world's military history -- the Mason Hill blast.

In 1915, the First World War was on the verge of white-hot fighting, and on the Western Front, the Germans organized a defense at Mount Mason with the strength of 5 infantry divisions. Mount Mason jutted 10 kilometers into the front of the British army, making it extremely difficult for the British to supply ammunition, food and drinking water. In order to relieve their own predicament, the British army pulled out this "nail" and decided to adopt the "heart-digging tactic" -- digging a tunnel at the foot of Mount Mason and then carrying out a major blast.

At the beginning of 1915, the British army sent excellent geologists to secretly survey the geological structure of Mount Mason, and after demonstration, the construction was scheduled to be organized in July of that year. Construction machinery used during the excavation of the underground railroad is used in the work. In order to avoid detection by German aircraft, the British adopted the method of secret construction, and transferred and camouflaged the excavated ballast. The British army spent 2 years digging 22 tunnels, each of which was 300 meters ~ 400 meters long, 25 meters ~ 36 meters deep, and some sections were up to 50 meters deep, and 600 tons of explosives were piled up in these tunnels.

At 3:10 a.m. on June 7, 1917, as green and yellow flares lit up the night sky, the British ignited the buried explosives, and the charges of 19 tunnels exploded (the charges of the other 3 tunnels failed to detonate due to malfunction). As a result of this explosion, most of the fortifications of the German army on Mount Mason were blown up, 20,000 officers and men were killed and wounded, and more than 7,000 officers and men were captured.

The success of the bombing of Mount Mason allowed the British army to improve the battle situation in the Ypres area and created favorable conditions for the British army to carry out the next campaign.

But to blast the tunnel, you have to have gunpowder. But gunpowder is one of the four great inventions of China, and now even arquebuses have not spread in the island country of Japan!

It is a mixture of charcoal powder, sulfur powder and powder, in the mixture, the mass fraction of the three components is approximately: 75%, charcoal 15%,

Sulfur 10%. In the reaction equation, the ratio of the three reactant coefficients (which should be called stoichiometry according to the national standard) is 1:2:3, which can be called "one sulfur, two nitrate and three charcoal" for the convenience of memory.

Due to the ignition of which, the three substances react violently, producing a large amount of gas and emitting a large amount of heat. In a confined space, the gas expands rapidly when heated and causes an explosion.

However, these problems are nothing, because Echigo has gold and silver mountains.

"Bullet main hall, please borrow it in the next batch of miners." Asadashi knew that Echigo definitely had gunpowder. Akida Castle is a mountain castle, so it is not easy to detect movement underground like Heijo Castle.

"Jing Gang, you go and help the repair doctor find the miners, and the rest of you besiege the city!" The girl set up her camp in her first residence----- Tochio Castle. And it's so close to Akida Castle.

Chaoding's idea was good, but he was disappointed. There were only 200 barrels of gunpowder in the entire Echigo, and only half of it could be used directly for tunnel blasting.

Naoe Keixuna told Asadachi a piece of good news, that is, the mountain of Shoda Castle was empty.

Hidetada hollowed out part of the mountain to hoard grain, grass, and ordnance, and the news was made known to the other Nagao retainers because he had mobilized a large number of people.

After the Nagao family mobilized 15,000 troops, at the suggestion of the court, 10,000 of them were used as the encirclement army, and the 5,000 troops were dug tunnels together with the local people.

Hidetada Akita only saw that the Nagao family had mobilized a large number of people, but he didn't know their mission, so he could only let it go.