Japanese Attack Ships Opposing Mongol Invasion

From the Mδko Shūrai Ekotoba (Illustrated Account of the Mongol Invasion) scrolls, artist unknown

Original (dating to late 13th century) in Museum of the Imperial Collections, Imperial Palace, Tokyo, Japan

(Unless specified, all illustrations are courtesy of Wikipedia)

Today in Military History: August 13-14, 1281

Today's history lesson brings together the Mongol armies of Kublai Khan – grandson of Genghis – and the early samurai of Japan. It also ties in an extreme meteorological event and the "special attack units" used by Japanese pilots near the end of the Second World War.

Background

By the year 1265, the Mongol Empire stretched from modern-day Ukraine in the west to Korea in the east, from south-central Siberia in the north to Iran in the southwest to central China in the southeast. These Asiatic horsemen were well trained, well equipped, and highly disciplined. Even when the Great Khan himself died in 1227, his successors and their generals continued his drive to conquer the world as they knew it. Even when they suffered a reverse (as against the Mamelukes in 1260), the Mongol armies ranged as far west as Hungary and Poland, defeating some of the best armies of western Europe. Often it was something as simple as the death of the reigning khan that halted the Mongols from continuing their depredations.



Kublai Khan, founder of Yuan (Mongol) Dynasty

Reigned 1260-1294

Kublai Khan was recognized as the Mongolian Great Khan in 1264, after a four-year civil war with his younger brother Ariq Böke. Two years later, in his continuing attempt to conquer the known world, Kublai sent a letter addressed to the "King of Japan" along with several emissaries. The letter urged the Japanese to become a vassal of the Mongols. The regent of the Japanese court, who controlled the reigning emperor, decided to studiously ignore the letter, hoping the non-answer would speak volumes. Over the next six years, five more attempts were made to force the Japanese to submit, none were successful.



Map of Mongol Empire c. 1260, showing major campaigns (1207-1258)

(Courtesy Department of History, University of Minnesota, www.hist.umn.edu)

First Mongol Attack on Japan

Finally, in 1274 Kublai Khan made the decision to launch an invasion of Japan. An invasion fleet of 300 large ships and 400-500 smaller ones, sailed from Korea carrying 15,000 Mongol and Chinese troops and 8000 Korean soldiers. Other sources say the Mongol army may have numbered up to 40,000 men.

After sailing across the Korea Strait, the invasion force landed on the island of Tsushima on November 4, subduing opposition after nine days of fighting. The Mongol fleet then sailed for the island of Iki, just off the coast of Kyushu, the southernmost island of the Japanese archipelago. Finally, on December 19 several Mongol landings and raids were launched, with the largest taking place at Hakata Bay.



Map of Kyushu (Hakata Bay is left of the "Fukuoka" prefecture label)

The two armies had different styles of fighting. The Mongol army was led by large units of Mongol horsemen firing clouds of arrows. These horsemen were supplemented by Korean and Chinese foot soldiers, usually wielding spears and interwoven bamboo shields. The Chinese members of this invasion force also included siege engineers who utilized catapults and slings to fire metal or ceramic canisters filled with gunpowder and metal shrapnel. The noise of these exploding devices – as well as the drums and gongs the Mongols used to signal orders to various units – disconcerted the Japanese troops at first.



"Samurai on horseback, wearing armor and horned helmet…"

Artist unknown, produced c. 1878

The Japanese defense forces were rather small, numbering perhaps as few as 4000 and as large as 10,000 soldiers all told. The samurai dominated the command structure of the island kingdom's military. At this time period, samurai were better known as mounted archers. During warfare in Japan, individual samurai would emerge from an army's ranks and issue challenges to any enemy samurai who would desire to gain a reputation. In this way, they were similar to western European knights. These men also had the katana (longsword) for which later historians – and historical epics by Japanese filmmaker Akira Kurosawa – would make famous.

In addition, samurai had at their command a number of retainers, called ashigaru, who provided the back-up foot soldiers to the samurai's mounted combat. In this early period, ashigaru wore minimal armor, were armed with pikes, swords, polearms, and bows. They also used thick wooden shields as makeshift field fortifications.



Early Samurai ashigaru, c. 1274

(Illustration courtesy of www.dbaol.com)

At first, the Mongol way of war confused the Japanese, as they saw no honor in the attacks of massed horsemen on singular samurai. The Mongol use of poisoned arrows and exploding bombs were also somewhat off-putting to the samurai. Soon, the Chinese and Korean footmen came into contact with the other Japanese soldiers. Along the coast of Kyushu near Hakata Bay a number of skirmishes tok place. Eventually, a bow-armed samurai shot a Mongol general, killing him. After this event, the Mongols decided the cost of the initial battle was too high.



Japanese samurai attacked by Mongol and Korean soldiers (note exploding bomb in center)

From the 2nd Mδko Shūrai Ekotoba scroll, 18th century copy

The next day, December 20, the Mongols and their allies re-embarked onto their ships. During this phase, severe thunderstorms were lashing the area of Hakata, perhaps the prelude to a tropical storm. By the next morning, all the Mongol ships were gone. The Japanese believed that local Shinto priests had contributed to the victory by praying to the numerous gods, who sent storms and "contrary winds" to break up the Mongol fleet. Korean records indicate that it took the Mongol fleet a month to return to its home ports due to the weather. Those same records state that the Mongol army suffered 33 percent casualties (13,000 men to be precise), but do not state whether they were all from fighting with the Japanese or from drowning. [One Mongol general claimed they were opposed by a Japanese army of 100,000 men…]

Preparations for a Second Mongol Attack on Japan

Despite their victory, the Japanese were convinced that the Mongols would return, this time in greater force – and they were correct. Several Mongol ambassadors came to Japan between 1275 and 1280; most were beheaded on the spot. Late in 1280, Kublai Khan decided to launch a massive invasion to dwarf the first attempt.

Kublai Khan directed his Korean and Song Chinese vassals to begin a massive shipbuilding campaign. By this time, the southern Song Empire had been conquered by the Mongols. The Koreans readily complied. The Song, however, whether out of malice or artistic integrity, took longer than the Mongol ruler wished to build their ships. Consequently, many Song vessels were not well built. In frustration, the Mongols began impressing Chinese sailors and soldiers and commandeering flat-bottomed riverboats and barges to carry the invasion army to Japan. [One historical sources states that Chinese criminals had their prison sentences commuted, if they agreed to join the invasion force.]



Typical Sung royal navy vessel, 13th century;

Ships of similar design were used by the Mongols in the 1281 invasion of Japan

(Illustration courtesy of www.allempires.com)

The samurai of Kyushu had not been idle since the first invasion seven years previously. Expecting an almost immediate return invasion, the local Japanese warlords ordered the construction of nearly 12 miles of walls east and west of Hakata Bay. These walls were between 2-3 meters high, and up to 3 meters thick, and about 50 meters from the shoreline. Many local samurai formed a coastal guard to warn the rest of Kyushu in the event of a Mongol return. There are even records indicating that the Japanese were planning a retaliatory raid on Korea, but that apparently never came to fruition.

This second Mongol attack on Japan was to be a two-prong offensive. An "Eastern Route" army – said to contain 40,000 men – had orders to sail from Korea, leaving on May 22, 1281. Contrary winds, and the enormous size of the fleet of 900 ships, resulted in a slower crossing to Japan than occurred in 1274. The Eastern army's first objective was to capture Iki island as a forward base, then await the arrival of the "Southern Route" army. This second force was made up of an estimated 3500 ship of various sizes, carrying 100,000 soldiers. [The figures for the two land forces are surely exaggerations.] Then, when the two forces combined, the Mongols would land and conquer the nation of the recalcitrant samurai. The Mongols were so sure of their victory that, along with weapons and armor, local blacksmiths were ordered to forge farm implements.

Second Mongol Invasion of Japan, 1281

Arriving at Iki island on June 12, the Eastern Route army subdued Japanese resistance after nine days. Then, the officers of the Eastern Route army made an extraordinary decision. Their orders said they were to wait and rendezvous with the Southern Route Army, scheduled to occur on July 2. However, the Eastern Route leaders ignored those orders. On June 21,about 300 ships sailed east and attacked Nagato province on the western tip of the island of Honshu. No records exist of exactly what occurred, but the local defense forces drove the Mongols off. The invaders returned to Iki.



Samurai maneuvering to attack Mongols in 1281; from 2nd Mδko Shūrai Ekotoba scroll, 18th century copy

Meanwhile, the rest of the Eastern Route army made another attempt to come ashore at Hakata Bay on the same day as the attack on Honshu. This time, however, the local samurai were prepared. Some Mongol troops came ashore, but they were met with volleys of arrows from ashigaru and samurai using the defensive wall. After a couple of hours, the Mongol forces withdrew to their ships. It was then decided to occupy two small islands in the bay, Shiga and Noko. The Mongols hoped to use them as base camps for further operations in the area.

The Mongols did not take into account the ingenuity of their Japanese opponents. That night, a large number of Japanese boats were loaded with samurai and ashigaru, then rowed out to the anchored Mongol fleet. Using grappling hooks and the collapsible masts of the small boats, the Japanese soldiers boarded the Mongol vessels and began killing any Mongol they could find. To prove their bravery, many a samurai took back to shore a severed Mongol, Korean, or Chinese head. Shiga Island was connected to the mainland by a sandbar; many samurai negotiated the narrow sandbar and attacked Mongols encamped on the island. There are also local narratives saying that some samurai swam out to the Mongol ships to launch their attacks.



Samurai boarding Mongol ships, from the 2nd Mδko Shūrai Ekotoba scroll, 18th century copy

For the next week, these Japanese "little ship" attacks continued in earnest. Finally, in the first week of July, the Mongol Eastern Route fleet decided to retreat back to Iki Island. Finally, in early August, the Southern Route fleet appeared, and the two fleets rendezvoused outside the port of Hirado, near the town of Nagasaki. The Mongols and their allies entered Imari Bay 30 miles southwest of Hakata, preparing to unload their soldiers to make an end-run around the defensive sea wall at Hakata Bay.

Unfortunately, on the night of August 12, the local samurai and their retainers launched their own "little ship" attacks on the Mongol fleet. These attacks were of such volume and ferocity that the next day the Mongol commanders made a fateful decision. All the largest Sung-constructed ships were ordered moored next to each other, connected by chains. Wooden planks were laid connecting the large ships together like fighting platforms.

Nature Intervenes; "Divine Wind"

On the night of August 13, 1281 storm winds began blowing from the southwest. Within hours, these winds picked up speed and before long were howling down on the anchored Mongol fleet. [Modern meteorologists estimate the typhoons winds peaked at over 75 mph.] With most of the fleet tied together, there was no way for them to maneuver or escape. In addition, most of the Sung ships impressed by the Mongols were flat-bottomed river vessels, which without the deep keels of the larger vessels, began capsizing and sinking very quickly. The typhoon blew for two full days.



"Mongols Invasion" Ink and water colors on paper

By Kikuchi Yoosai (1847), Tokyo National Museum

When the storm moved out on August 15, nearly 90 percent of the Mongol fleet was sunk, and thousands of the sailors and soldiers were drowned. One Japanese account claimed that Mongol and Chinese corpses filled Imari Bay that a man could walk across the bay. The decision was made to return to China, and the remains of the invasion fleet began to sail homeward.

Aftermath

Contemporary records estimate that between 60 and 90 percent of the personnel in the Mongol fleets lost their lives. This included those who survived, clinging to pieces of destroyed ships in Imari Bay who were captured and summarily executed by the samurai. Japanese casualties are unknown.

Footnote #1: This unusual victory thanks to the intervention of nature – or, to the Japanese mind, from the successful use of prayer to their gods – became a central part of the Japanese national psyche. The islands of Nippon were believed to be divinely protected. The typhoon was labeled kamikaze, or "divine wind." The events of 1281 would be used 650+ years later as the inspiration for the Japanese pilots who flew bomb-laden planes into Allied warships off the coast of Japan, hoping to save their homeland from defeat in the latter months of the Second World War.



Japanese "Judy" divebomber descending on USS Essex (CV-9), November 25, 1944

Footnote #2: In October of 2011, archeologists discovered a Sung shipwreck buried under three feet of silt 75 below the surface of Imari Bay. Various items were found, including the exploding cylinders (see below), stone anchors, bundles of arrows, and even bricks. They have been connected to the Mongol invasion of 1281.



Chinese exploding cylinders, excavated from Imari Bay in October of 2011

Footnote #3: It is likely the Mongols felt, if they kept to their original invasion schedule, the two fleets would have made successful landings and begun the conquest of Japan before the worst part of the typhoon season commenced. Like the Atlantic-Caribbean hurricane season, the northwest Pacific typhoon season is generally worst during the time period of June through November, with the month of August the worst month for typhoons. Meteorological data for 1959-2005 show an average of 6.6 typhoons each August in that area of the world.