Here's What You Need to Remember: The Great Wall actually proved reasonably effective for a defensive obstacle built six centuries earlier, and Chinese soldiers showed courage and adaptability in employing the antiquated weapons at their disposal. But static defenses and sheer courage by themselves could not prevail in the new age of mobile warfare that would soon consume the world.

The Great Wall reigns as a symbol of Chinese nationhood, over 3,800 miles of fortified walls (or 5,500, if you count trenches and natural barriers) built to shield the settled peoples of the North China Plain from the depredations of nomadic horse-riding tribes to the north. While the wall undoubtedly posed a formidable obstacle against horsemen armed with spears and bows, less than a century ago today’s scenic attraction was also used in a desperate defensive battle against a foe armed with tanks, airplanes, naval destroyers and machine guns.

Though earlier “long walls” made of rammed earth and gravel appeared in China as early as the third century BC, most of the stone walls standing today date back to the fourteenth century, the products of a vigorous construction program undertaken by the Ming Dynasty. This was not actually one huge connected wall, but a series of walls spanning over key mountain passes, with gaps filled by natural obstacles and trenches. Furthermore, key mountain passes were often guarded by multiple walls, so that defenders could fall back to a second fortified line if the first was breached.

The northeasternmost outpost of the Great Wall is called Shanhaiguan, or the “Pass of Mountain and Sea,” as its Old Dragon’s Head rampart extends into the shallows of the Bohai Sea. Since, late in the nineteenth century, Japan’s modernized military had profited from political instability in China to nibble away territory with its powerful Kwantung Army—including colonizing all of Korea. Due to its involvement in suppressing the Boxer Rebellion in 1901, Japan was allowed by protocol to maintain a two-hundred-man Japanese contingent at Shanhaiguan alongside the Chinese garrison.

By the 1930s, militarists were ascendant in Tokyo, and ready to embark on expansionist adventures without authorization from the civilian government. In 1931, two Japanese officers blew up a length of their own railway line near Mukden (now Shenyang), China. Japan claimed the Chinese had perpetrated the sabotage and used it as a pretext to invade three provinces which were then formed into the puppet state of Manchuria. The Chinese Nationalist Kuomintang government of Chiang Kai-shek ordered his troops not to fight the Japanese invasion, as he was then concentrating on consolidating his power over regional warlords and eradicating Communist insurgents.

Then on the ides of May in 1932, a group of cadets assassinated Japanese prime minister Inukai Tsuyoshi, who opposed military aggression. The perpetrators were given light sentences, and senior Army leaders realized they could act with near impunity.

On New Year’s Day 1933, somebody (most likely the Japanese themselves) detonated grenades and shot a rifle into the air on the Manchurian side of the wall. The following day, the Japanese commander at Shanhaiguan demanded the Chinese troops withdraw from wall for their “terrorist” acts. That demand did not go over well, and a Japanese soldier was shot and killed in a confrontation.

The following morning, the Imperial Japanese Navy destroyers Fuyō and Karukaya of the Second Expeditionary Fleet began blasting the forty-five-foot-high walls of Shanhaiguan with their 120-millimeter guns. The bombardment was joined by nineteen field howitzers and four armored trains, while a half-dozen bombers showered the ramparts with high explosives. Meanwhile, infantry of the Japanese army’s Eighth Shaidan (Division) forded the wall’s moat with a pontoon bridge, threw up siege ladders and stormed the ramparts, while three lumbering new Type 89 I-Go tanks provided covering fire with their stubby-barreled fifty-seven-millimeter cannons.

The Chinese troops of the 626th Regiment were badly outgunned. They disposed of some rifles and a few light machine guns, but many had only pistols and dadao—heavy single-edge steel chopping swords variously termed “Chinese broadswords” or “big knives.” Their heaviest weapons were a small number of Maxim machine guns and light mortars. They sustained heavy casualties, including the loss of a battalion commander, and withdrew out the back gate by the end of the day.

On February 23, Governor General Muto Nobuyoshi embarked on the next phase of the campaign with Operation Nekka, aimed at capturing Rehe Province, also known as Jahol. Located northeast of Beijing, Rehe was claimed by Manchuria and possessed valuable opium fields. The Japanese first unsuccessfully attempted to buy off the region’s corrupt warlord, Tang Yulin, before deciding to invade.

For the attack, Nobuyoshi mustered the Sixth and Eighth Shaidan, one cavalry and two independent infantry brigades, and the First Special Tank Company, equipped with eleven Type 89 infantry tanks and diminutive Type 92 tankettes. Manchuria committed an additional forty-two-thousand allied Chinese troops.

Zhang Xueliang, the commander of the Nationalist Northeast Army, was then in the throes of opium addiction, and his leadership was so ineffectual that Japanese cavalry and tanks captured the provincial capital of Changde in just nine days, which was then incorporated under Manchurian governance. Tang Yulin fled, tarrying only to load a convoy full of opium and valuables.

Muto then ordered his troops to pivot southward, realizing the slow Chinese response gave them an opportunity to dismantle the defenses surrounding Beijing. They were confronted by four mountain passes situated along a snaking belt of rugged Great Wall fortifications; from west to east, these were Gubeikou, Xifengkou, Lengkou and Jielingkou. Because the gates were situated in between extremely steep mountains, Japanese troops would have no choice but to storm the ramparts in head-on attacks.

Meanwhile, Chiang Kai-shek had realized the precarious situation north of Beijing and pressured Zhang into handing over command to He Yingqin, the “Lucky General.” To buy time for reinforcements to arrive from south and central China, General He dispatched four infantry corps (averaging fourteen thousand men each) to engage the Japanese in a fight for the Great Wall gates. The Twenty-Ninth Corps under Gen. Song Zheyuan headed for Xifengkou, the Thirty-Second Corps sallied forth to take back Lengkou, and the Seventeenth and elements of Sixty-Seventh Corps to defended Gubeikou, where there was a fifteen-mile-wide pass with the scenic Nantianmen (Southern Heavenly Gate) as its lynchpin.

According to an article by Jiaxin Du in Military History magazine, to compensate for their lack of firepower, Chinese commanders did their best to engage the Japanese in short-range ambushes, giving their sword- and pistol-equipped infantry a chance to close with their Japanese adversaries armed with Arisaka Type 38 bolt-action rifles and Nambu light machine guns. Several snow-covered stretches of the wall changed hands daily, as one side and then the other seized the barbicans in bloody close-quarter melees.

Gen. Song Zhongyuan of the Twenty-Ninth Corps even formed a five-hundred-man “Broadsword Battalion” composed of soldiers trained in the martial arts. Late on March 11, two local hunters guided the Broadsword Battalion and two infantry brigades down a hunting trail behind Japanese lines. After midnight, a horde of sword-wielding warriors overran a sleeping cavalry unit on the right flank, while the left force burst into a Japanese artillery encampment and command post at Baitaizi. Hurling grenades and slashing with their swords, they reportedly spiked eighteen artillery pieces and several armored vehicles before withdrawing at dawn. The Chinese troops at Xifengkou would launch several more night raids and repel twenty attacks on the ancient stone fortifications.

Meanwhile, on March 7 the Seventeenth Corps took Gubeikou back from Japanese forces—you can see the vertiginous terrain there in this photo. Five days later it was driven from its position by the Japanese Eighth Shaidan after several divisional and regimental commanders were killed or wounded. However, continuing mobile defensive actions and frequent night raids in which they made effective use of German-supplied MP18 submachine guns kept Japanese troops bottled up along the pass for a month.

However, the Japanese infantry were persistent and willing to wade into a melee with bayonets. More importantly, they had air, armored and artillery support, and the Chinese did not. The Great Wall defensive line began to fall apart early in April. On April 11, the Sixth Shaidan broke through Lengkou pass and began advancing toward Qian’an, cutting the supply lines of the Chinese units defending neighboring passes. One by one the defending corps were driven back, most having suffered around 33 percent casualties. By May 20, the last Chinese garrisons on the Great Wall were forced to retreat, leaving the road open to Beijing and Tianjin.

However, peace talks had been grinding on in Shanghai during the fighting, and Western nations, fearing for the safety of their citizens in Beijing, pressured the Japanese government to reign in the Kwantung Army. On May 22 China acceded to the Tanggu Truce, bringing a halt to the fighting largely on Japanese terms. As a condition of the truce, a so-called demilitarized zone was extended sixty miles south of the Great Wall which only Japanese-allied troops could enter.