Korean 'super rocket' terrified Japanese samurai in the 15th century

A hwacha rocket launcher was capable of firing 50 large arrows at once, penetrating many of the best protective armors of the 15th century.

14th-century Korean rocket launcher that terrified Japanese samurai

Hwacha system firing test

In the late 14th century, the Joseon Dynasty of Korea launched an espionage campaign to acquire secret Chinese gunpowder and rocket technology to fight against Japanese pirates. This campaign helped Korea develop the hwacha "super rocket" that would be the nightmare of pirates and Japanese samurai armies in the 15th century, according to War is Boring.

During this period, China was the world leader in gunpowder technology. However, the rockets it produced at that time were too inaccurate, difficult to cause damage, and were often used only to scare the horses in the enemy cavalry. In addition, China was not willing to share technology with North Korea, despite the long-standing friendly relationship between the two countries.

In 1377, a Chinese merchant agreed to ship a batch of manufacturing documents and gunpowder samples to Korea, while inventor Choe Mu-seon discovered a way to synthesize gunpowder from soil. The resulting technology helped Korea develop a series of explosive weapons such as rockets, cannons, and arquebuses. From 1380, Korea began using these weapons to destroy pirates in naval battles.

The Korean expeditionary fleet completely destroyed the Japanese pirate force in 1419 with the powerful support of hwacha rockets, one of the world's first multiple rocket launcher systems.

Hwacha is a product of two inventors.Yi Do and Choi Hae-san developed it. They believed that it was difficult for a single rocket to hit a target due to its low accuracy, but launching dozens to hundreds of arrows at once would ensure the destruction of everything in sight. This rocket system uses a Chinese design, but can launch 50-100 arrows at the same time, far surpassing the system developed by China.

Each hwacha complex is mounted on two wheels for increased mobility. The launcher consists of dozens of tubes placed in rows, inside which can hold 1.1 m long arrows with paper tubes filled with propellant near the tip. The arrows are all connected by slow-burning fuses, allowing them to fire completely in 2-3 seconds with just one ignition.

Hwacha launcher with arrow attached to gunpowder tube. Photo: Wikipedia.

The Hwacha was made of wood, making it much easier to maneuver than the cast iron cannons of the time, while the crew only needed a maximum of four men. The Hwacha had an effective range of about 100-150 m, and tests showed that the heavy arrows were capable of penetrating all types of armor and shields at this distance. The range of the hwacha could be increased to 300-500 m if fired from a high position and using light arrows.

Contemporary artillery was used in siege warfare, but hwacha were used against infantry to defend the Joseon Dynasty's citadels. Korea deployed at least 130 hwacha around Seoul and its northern border to prevent raids by the Jurchen tribe.

The North Korean military also mounted the weapon on panokseon warships, which were typically 20-30 meters long and had flat bottoms for use in shallow waters close to shore. The Hwacha were small and light enough to maneuver on deck, providing firepower from all directions.

Nightmare for Japanese Samurai

In 1592, Japanese warlord Toyotomi Hideyoshi launched a surprise attack on Korea with 158,000 troops, starting the Imjin War. Toyotomi's goal was to conquer China, but the Joseon court refused to grant the Japanese army passage, prompting the Japanese warlord to invade Korea.

The Ming Dynasty allied with the Joseon army to push the Japanese out of Pyongyang and launched an attack to regain control of Seoul. However, the attack failed, the Ming expeditionary force was defeated, and the task of retaking Seoul became the responsibility of the Korean army.

By February 1593, General Kwon Yul had assembled an army of 2,300 soldiers at the ancient fortress of Haengjiu, which had only one approach and was about 10 kilometers from Seoul. This force was supplemented by 700 men from the surrounding area, including monks and female warriors.

Over three days, Kwon Yul built a dense defense system, with at least 40 hwacha systems. Facing them were 30,000 samurai and Japanese soldiers, under the command of famous generals such as Ukita Hideie, Kato Kiyomasa and Kuroda Nagasama.

The Japanese army launched three continuous attacks on the ancient fortress from the morning of February 12, 1593. However, the hwacha system and Joseon archers continuously rained arrows, while Korean soldiers threw large rocks, poured boiling oil and molten metal at the enemy. The thick defense repelled all Japanese attacks.

Hwacha can use small arrows to increase range. Photo: Wikipedia.

At noon on February 12, 1593, the fourth wave of attacks led by Ukita broke through the outermost defense of the Korean army. However, the Japanese forces were still repelled by the hwacha rocket batteries, while Ukita was seriously injured. By the afternoon, the supply of hwacha arrows began to run out, and the Korean army faced the risk of being completely annihilated.

Just as the Japanese were preparing for their final assault, the Korean soldiers inside the castle were reinforced with 10,000 arrows. They were quickly loaded into all the hwacha bases, creating a storm of missiles that rained down on the charging Japanese samurai. By the night of February 12, all three famous Japanese generals were wounded by hwacha and forced to retreat. The Japanese suffered a total of 1,000 deaths after nine attacks.

Three months later, Korean forces retook Seoul. General Kwon Yul claimed that the hwacha's formidable firepower was the decisive factor in repelling the Japanese in this campaign.

The Imjin War lasted for another five years, devastating much of Korea. The decisive battle took place at dawn on December 16, 1598, when a force of 63 Chinese warships and 82 Korean panokseon secretly raided a fleet of 500 Japanese warships south of the Korean peninsula.

The Korean side took full advantage of the firepower of the hwacha and cannons. By the morning of December 16, the Japanese fleet had lost more than half of its warships and was forced to withdraw. Eight days later, the entire Japanese army had completed its withdrawal from the Korean peninsula.

According to VNE