As early as the mid-19th century, the German geologist Richthofen had traveled long distances to the Shandong Peninsula, and he found that Qingdao was a battleground for soldiers. His views attracted the attention of Kaiser Wilhelm II, and for this reason, Germany conducted several investigations in Qingdao.

In November of the 23rd year of Guangxu, two German missionaries were killed, and Wilhelm II was overjoyed and said bluntly: "We have finally waited for the long-awaited excuse." "After reaching a tacit agreement with Russia, the German fleet broke into the Jiaozhou Bay of Shandong. The following year, the Qing government was forced to lease Jiaozhou Bay to Germany for 99 years. In fact, Qingdao was a German lease, but in reality it was no different from a colony. It is a fact that in the postal system at the end of the Qing Dynasty, sending letters to Jiaozhou Bay was included in the classification of sending letters to Germany, and Qingdao became a "territory" of Germany. After that, Germany seized the right to build the Jiaoji Railway from Qingdao to Jinan, although it was blocked by the rising Wuyi New Army in the line of Lancun in Jiaozhou, but in the end, Qingdao still became the base of the German Navy's East Asian Fleet to protect Germany's possessions in the Pacific.

In order to run the Qingdao fortress well, Germany spent a lot of thought. The subsequent Gengzi Revolution made the German colonial authorities consider the defense of Qingdao more seriously. After a long period of construction, the German army arranged two major defense systems on land and sea in Qingdao, and finally formed the "Qingdao Fortress".

Ground defense system: In the direction of the interior, the Germans laid out three lines of defense. The first line of defense was built along the steep ridges that separated the city of Qingdao and the port from the Shandong Peninsula, but this line was not coherent and the Germans did not have so many troops to hold it, so the Germans did not expect them to really stop the enemy's footsteps, except to delay the enemy's advance. The second line of defense was 17 kilometers long and was also built along the steep mountains. The last line of defense was between several hills in the city, and the Germans built trenches, batteries and other fortifications at Xiaoyu Hill and Guanxiang Mountain.

Maritime defense system: In the direction of the Yellow Sea, the Germans laid mines at the waterway of the port, built 4 artillery batteries, and 5 multi-sided defensive fortresses. Although some of the cannons were relatively old guns left by the Qing army in the Jiaozhou Bay Fort, and some were dismantled from the Qing army's fort at Dagukou, which was forced to be dismantled according to the "Xinchou Treaty", on the whole, Qingdao's defense facilities were relatively complete and had been well operated.

According to the statistics published in the "Global Military" article, on the eve of World War I, the German army stationed in Qingdao had 130 shore defense guns, more than 30 120 and 88 mm field guns, and dozens of the most advanced Maxim machine guns at that time (in the Battle of the Somme in World War I, the German army relied on this gun to set a record of 60,000 British casualties in one day), and the navy had 16 warships in the port. In terms of weaponry, due to the relatively developed German industry, especially the munitions industry, the German army's weaponry was superior to that of the Japanese army, which was about to attack.

Of course, there is never an impregnable line of defense in the world, and we find that every supposedly impregnable line of defense has its own day of collapse, and the German "Qingdao Fortress" suffered the same fate as the later famous "Maginot Line".

At the end of August of the sixth year of the Republic, war clouds had begun to gather over Qingdao, and the Chinese in the city had taken refuge in neighboring Dengzhou or Qingzhou, and the worst of them also hid in the Jiaonan Jiaozhou countryside on the other side.

In fact, even before the British ambassador to Japan sent a request to the Japanese foreign minister to enter the war on 7 August, Germany had a premonition that war was approaching. In early August, the German Emperor declared Jiaozhou Bay on military alert, and German expatriates in the Far East were called up into the army or reservists. The Empress Elizabeth, an important German partner and the only cruiser of the Austro-Hungarian Empire in the Far East, also sailed into the port of Qingdao and joined the ranks of the defense of the fortress of Qingdao.

However, the seemingly impregnable "Qingdao Fortress" of the German army had a major problem - insufficient troops. It is no wonder that Germany's military presence in East Asia was limited due to geography, and the German army's operational planning in the early years of World War I exacerbated the problem. In the European theater, in order to avoid a disadvantage in the two-front operation, the German General Staff formulated the "Schlieffen Plan". This famously gambling right hook plan was an attempt to achieve a quick victory, requiring the Germans to take advantage of the Russian government's inefficiency and poor transportation in the early stages of the war to capture Paris in a matter of weeks, and then defeat the Russians eastward. This plan objectively required the German army to concentrate its forces on the European continent, which further limited the size of the German garrison in Shandong, China. Thus, at the beginning of August, when the war was about to begin, the German Army in China was only 3,650 men. Some local Chinese who were incorporated into the German army were also used as cannon fodder to join the defenders, while the Japanese sent 50,000 men.

The Japanese army had sufficient troops and a strong desire for war, so they quickly issued an ultimatum. On 15 August, the Japanese Government issued an "ultimatum" to the German Government, demanding that the German Government unconditionally hand over Qingdao to Japan for the time being, and that the German Army and Navy withdraw from China on the grounds that all the concessions in Jiaozhou Bay would be returned to China (in fact, that is, to drive out the German tenants, and then Japan itself would lease Qingdao).

Faced with this ultimatum, the Germans, who had a rare sense of humor, gave an interesting answer: "Qingdao can be considered to be returned to China, but Japan should also return Taiwan to China." "Of course, the Japanese did not want Qingdao to return to the Chinese, otherwise they would not have to negotiate to prevent China from accepting Qingdao from the Germans, although the Germans were only talking.

In the face of Japan's hard* stance, the Germans also put on a posture of fighting to the end. Kaiser Wilhelm II personally telegraphed to Governor Melvadek, who was also the commander of the Qingdao Fortress: "Be sure to defend the Qingdao Fortress and fight to the last man." A dialogue that better reflects the German mentality is recorded in Aardton61 Robert's book The Asahi Samurai, in which the German Emperor Wilhelm II said, "It is more humiliating for me to surrender Tsingtao to the Japanese than to surrender Berlin to the Russians." Perhaps in William's mind, the Japanese were simply wild dogs that followed the lion and ate carrion, and the tiger could lose to the lion but would never let the wild dog bark.

On 23 August, Japan declared war on Germany on the grounds of its Anglo-Japanese alliance obligations after agreeing a one-month deadline with China. But what no one expected was that the outcome of this battle would be a dramatic scene.

On September 2, the Japanese army had mobilized 45,000 troops with the 18th Division as the main force, equipped with hundreds of heavy siege artillery, mountain artillery, field artillery, and a number of aircraft, and landed in Yantai, Shandong. Accompanied by the 18th Division of the National Defense Army, the Japanese army first passed through Huangxian, Yexian, Pingdu, Jimo and the towns along the Jiaoji Railway in five days, and finally entered the Jiaoao Governor's District, and stationed troops in Li Village to force Qingdao. Of course, in addition to the 18th Division, the other two instructors of the Wehrmacht were also assembled in the Qingzhou area, and they could encircle the Japanese army at any time, so the little devil still knew how to do it. The Germans on the perimeter retreated into the city after a little resistance, and the casualties in the perimeter battles were less than double digits, so neither the Japanese nor the Germans really understood the strength of their opponents.

However, the second line of defense was the commanding heights of Fushan, Yandun Mountain (now Xujiadong Mountain), Sifang Mountain, etc., and the Chinese laborers hired by Germany built temporary forts, dug trenches, fortifications, and transported supplies, etc., and were very active in preparing for war. However, at that time, the total strength of the German army stationed in Qingdao was less than 5,000 people, almost one-tenth of the Japanese offensive force, and shrinking the defense and preserving the strength of the German army in Qingdao became the only choice. As a result, only a small number of German light cavalry were on guard at Yangkou Bay, which was outside the outer line of defense. Without spending much ammunition, the landing Japanese repulsed the German alert force and advanced to Li Village, where they joined the main Japanese force heading south.

The Japanese Combined Fleet has dispatched more than 60 warships, large and small, to blockade Jiaozhou Bay and attack the German troops stationed in Qingdao from the sea, but because the Germans have laid a large number of mines in Jiaozhou Bay, the landing in the Laoshan Mountains on the east side of Qingdao has almost become the only option for the Japanese army. A few days later, another group of British troops with a total strength of about 2,000 men also landed in Yangkou Bay, including a group of bearded Indian soldiers.

The Japanese army became very arrogant because of the victory in the Russo-Japanese War, and at the same time as the main Japanese army departed, the construction of prisoner of war camps began in Japan. After the accumulation of troops, on September 26, the Japanese and British forces began to attack the periphery of Qingdao (this day was also the beginning of calculating the Japanese army's attack time in one month), and after a week of hard fighting, they gradually occupied the German outlying positions in Gushan, Loushan, Luohuanjian and other places.

On the second day after the Japanese troops landed at Yangkou Bay, the Germans sent 58 officers and men to the Fushan Heights to set up observation posts, and set up five fortifications, stockpiling 60,000 rounds of ammunition, 300 grenades, 2,000 flares, and enough food and water to last for eight days, preparing to deal with the Japanese army for a period of time. In order for the Japanese army to destroy the German batteries on various hills in the urban area of Qingdao, it was necessary to install large-caliber heavy artillery in the deep zone, but the existence of German observation posts made the Japanese army have nothing to hide.

The start of the battle of Fushan has become an important node in the offensive and defensive battle of Qingdao, the previous temptation between the two sides has ended, and the next is the contest of flesh and steel, neither the German defenders nor the Japanese army thought that this battle far from the main battlefield in Europe would actually be a sea of volcanic blood.