thumb|Re-constructed in the 1990s, the Japanese embassy in Berlin's [[Hiroshima Street was originally built from 1938 to 1942, and thus has been a symbol for German–Japanese relations since that time.]]
thumb|Embassy of Germany in Japan
Germany–Japan relations (; ) are the current and historical relations between the Federal Republic of Germany and Japan. , Germany and Japan are world's 3rd and 4th largest economies by nominal GDP. They maintain extensive political, cultural, scientific and economic cooperation. Japan also has close relations with the European Union, of which Germany is the most populous member.
Japan had limited contact with Germans during its isolationist sakoku period, via the Dutch trading port of Dejima. During the bakumatsu opening period, the Kingdom of Prussia established diplomatic relations in 1860 with the Eulenburg expedition. Japan modernized rapidly after the Meiji Restoration of 1868, often using German models through intense intellectual and cultural exchange. After aligning with Britain in 1902, the Empire of Japan declared war on the German Empire in 1914, one month into World War I. Japan fought one major battle in the war's Asia-Pacific theatre, the Siege of Tsingtao. It acquired from Germany its Kiautschou Bay Leased Territory leading to the Shandong Problem, as well as the South Seas Mandate.
In the 1930s, both countries adopted aggressive ultranationalist attitudes toward their respective regions, Nazism and Kokkashugi, leading to a rapprochement. The Anti-Comintern Pact between the countries grew into the political and military alliance known as the Axis powers, to which Fascist Italy and other countries later acceded. The countries also developed an industrial cooperation, and initially used the Trans-Siberian Railway. During World War II, however, due to the German invasion of the Soviet Union, Japan and Germany fought the largely separate Pacific War and European theatre, only exchanging cargo via the Yanagi and U-boat submarine missions. Germany surrendered in May 1945, three months before Japan.
After World War II, the Allies occupied Germany until 1949 and the US occupied Japan until 1952. Among worldwide growth, Germany experienced the Wirtschaftswunder ("economic miracle") and Japan later saw its own economic miracle. Bilateral relations, now focused on economic issues, were soon re-established. Both countries are members of economic organizations including the G7, G20, OECD, and World Trade Organization. They are also members of the G4 nations and the International Criminal Court. Among their scientific cooperation, both countries contribute to the ITER nuclear fusion program, and via the European Space Agency and JAXA.
According to a late 2023 Bertelsmann Foundation Poll, the Germans view Japan overwhelmingly positively, and regard that nation as less a competitor and more a partner. The Japanese views of Germany are positive as well, with 97% viewing Germany positively and only 3% viewing Germany negatively.
History
First contacts and end of Japanese isolation (before 1871)
thumb|[[Philipp Franz Balthasar von Siebold contributed greatly to Europe's perception of Japan.]]
Relations between Japan and Germany date from the Tokugawa shogunate (1603–1868), when Germans in Dutch service arrived in Japan to work for the Dutch East India Company (VOC). The first well-documented cases are those of the physicians Engelbert Kaempfer (1651–1716) and Philipp Franz Balthasar von Siebold (1796–1866) in the 1690s and 1820s, respectively. Both accompanied the director of the Dutch trading post at Dejima on the obligatory voyage to Edo to pay tribute to the shōgun. Siebold became the author of Nippon, Archiv zur Beschreibung von Japan (Nippon, Archive for the Description of Japan), one of the most valuable sources of information on Japan well into the 20th century; since 1979, his achievements have been recognised with an annual German award in his honour, the Philipp Franz von Siebold-Preis, granted to Japanese scientists. Von Siebold's second visit to Japan (1859–1862) became a disaster because he tried to influence Dutch politics in Japan and attempted to obtain a permanent post as a diplomat in that country.
In 1854, the United States pressured Japan into the Convention of Kanagawa, which ended Japan's isolation. It was considered an "unequal treaty" by the Japanese public, since the US did not reciprocate most of Japan's concessions with similar privileges. In many cases, Japan was effectively forced into a system of extraterritoriality that provided for the subjugation of foreign residents to the laws of their own consular courts instead of the Japanese law system, open up ports for trade, and later even allow Christian missionaries to enter the country. Shortly after the end of Japan's seclusion, in the so-called Bakumatsu period, the first German traders arrived in Japan. In 1860, Count Friedrich Albrecht zu Eulenburg led the Eulenburg Expedition to Japan as ambassador from Prussia, a leading regional state in the German Confederation at that time. After four months of negotiations, another "unequal treaty", officially dedicated to amity and commerce, was signed in January 1861 between Prussia and Japan.
Despite being considered one of the numerous unjust negotiations pressed on Japan during that time, the Eulenburg Expedition, and both the short- and long-term consequences of the treaty of amity and commerce, are today honoured as the beginning of official Japanese-German relations. To commemorate its 150th anniversary, events were held in both Germany and Japan from autumn 2010 through autumn 2011 hoping "to 'raise the treasures of [their] common past' in order to build a bridge to the future."
Japanese diplomatic mission in Prussia
In 1863, three years after von Eulenburg's visit in Tokyo, a Shogunal legation arrived at the Prussian court of King Wilhelm I and was greeted with a grandiose ceremony in Berlin. After the treaty was signed, Max von Brandt became diplomatic representative in Japan – first representing Prussia, and after 1866 representing the North German Confederation, and by 1871 representing the newly established German Empire.
In 1868, the Tokugawa shogunate was overthrown and the Empire of Japan under Emperor Meiji was established. With the return of power to the Tennō dynasty, Japan demanded a revocation of the "unequal treaties" with the western powers and a civil war ensued. During the conflict, German weapons trader Henry Schnell counselled and supplied weapons to the daimyō of Nagaoka, a land lord loyal to the Shogunate. One year later, the war ended with the defeat of the Tokugawa and the renegotiation of the "unequal treaties".
Modernization of Japan and educational exchange (1871–1885)
thumb|upright|right|Japanese minister [[Itō Hirobumi studied European constitutions in Berlin and Vienna in 1882 as templates for a Japanese legal basis.]]
With the start of the Meiji period (1868–1912), many Germans came to work in Japan as advisors to the new government as so-called "oyatoi gaikokujin" (, "hired foreigners") and contributed to the modernization of Japan, especially in the fields of medicine (Leopold Mueller, 1824–1894; Julius Scriba, 1848–1905; Erwin Bälz, 1849–1913), law (K. F. Hermann Roesler, 1834–1894; Albert Mosse, 1846–1925) and military affairs (K. W. Jacob Meckel, 1842–1906). Meckel had been invited by Japan's government in 1885 as an advisor to the Japanese general staff and as teacher at the Army War College. He spent three years in Japan, working with influential persons (including Katsura Tarō and Kawakami Soroku), thereby decisively contributing to the modernization of the Imperial Japanese Army. Meckel left behind a loyal group of Japanese admirers, who, after his death, had a bronze statue of him erected in front of his former army college in Tokyo. Overall, the Imperial Japanese Army intensively oriented its organization along Prusso-German lines when building a modern fighting force during the 1880s.
In 1889, the Constitution of the Empire of Japan was promulgated, greatly influenced by German legal scholars Rudolf von Gneist and Lorenz von Stein, whom the Meiji oligarch and future Prime Minister Itō Hirobumi (1841–1909) visited in Berlin and Vienna in 1882. At the request of the German government, Albert Mosse also met with Hirobumi and his group of government officials and scholars and gave a series of lectures on constitutional law, which helped to convince Hirobumi that the Prussian-style monarchical constitution was best-suited for Japan. In 1886, Mosse was invited to Japan on a three-year contract as "hired foreigner" to the Japanese government to assist Hirobumi and Inoue Kowashi in drafting the Meiji Constitution. He later worked on other important legal drafts, international agreements, and contracts and served as a cabinet advisor in the Home Ministry, assisting Prime Minister Yamagata Aritomo in establishing the draft laws and systems for local government. Dozens of Japanese students and military officers also went to Germany in the late 19th century, to study the German military system and receive military training at German army educational facilities and within the ranks of the German, mostly the Prussian army. For example, later famous writer Mori Rintarô (Mori Ōgai), who originally was an army doctor, received tutoring in the German language between 1872 and 1874, which was the primary language for medical education at the time. From 1884 to 1888, Ōgai visited Germany and developed an interest in European literature producing the first translations of the works of Goethe, Schiller, and Gerhart Hauptmann.
Cooling of relations and World War I (1885–1920)
thumb|A French political cartoon from 1898 depicting the imperial powers, including Germany and Japan, dividing the "Chinese cake" among them.
At the end of the 19th century, Japanese–German relations cooled due to Germany's, and in general Europe's, imperialist aspirations in East Asia. After the conclusion of the First Sino-Japanese War in April 1895, the Treaty of Shimonoseki was signed, which included several territorial cessions from China to Japan, most importantly Taiwan and the eastern portion of the bay of the Liaodong Peninsula including Port Arthur. However, Russia, France and Germany grew wary of an ever-expanding Japanese sphere of influence and wanted to take advantage of China's bad situation by expanding their own colonial possessions instead. The frictions culminated in the so-called "Triple Intervention" on 23 April 1895, when the three powers "urged" Japan to refrain from acquiring its awarded possessions on the Liaodong Peninsula.
Another stress test for German–Japanese relations was the Russo-Japanese War of 1904/05, during which Germany strongly supported Russia. This circumstance triggered the Japanese foreign ministry to proclaim that any ship delivering coal to Russian vessels within the war zone would be sunk. After the Russo-Japanese War, Germany insisted on reciprocity in the exchange of military officers and students, and in the following years, several German military officers were sent to Japan to study the Japanese military, which, after its victory over the tsarist army became a promising organization to study. However, Japan's growing power and influence also caused increased distrust on the German side.
thumb|left|German Bridge, built by the prisoners of [[Bandō Prisoner of War camp|Bandō POW camp during their captivity]]
The only major battle that took place between Japan and Germany was the siege of the German-controlled Chinese port of Tsingtao in Kiautschou Bay. The German forces held out from August until November 1914, under a total Japanese/British blockade, sustained artillery barrages and manpower odds of 6:1 – a fact that gave a morale boost during the siege as well as later in defeat. After Japanese troops stormed the city, the German dead were buried at Tsingtao and the remaining troops were transported to Japan where they were treated with respect at places like the Bandō Prisoner of War camp. In 1919, when Germany formally signed the Treaty of Versailles, all prisoners of war were set free and most returned to Europe.
Japan was a signatory of the Treaty of Versailles, which stipulated harsh repercussions for Germany. In the Pacific, Japan gained Germany's islands north of the equator (the Marshall Islands, the Carolines, the Marianas, the Palau Islands) and Kiautschou/Tsingtao in China. Article 156 of the Treaty also transferred German concessions in Shandong to Japan rather than returning sovereign authority to the Republic of China, an issue soon to be known as Shandong Problem. Chinese outrage over this provision led to demonstrations, and a cultural movement known as the May Fourth Movement influenced China not to sign the treaty. China declared the end of its war against Germany in September 1919 and signed a separate treaty with Germany in 1921. This fact greatly contributed to Germany relying on China, and not Japan, as its strategic partner in East Asia for the coming years.
Rapprochement, Axis and World War II (1920–1945)
Reestablishment of relations and Sino-Japanese dilemma
thumb|upright|As German ambassador in Tokyo from 1920 to 1928, Wilhelm Solf initiated the re-establishment of good German–Japanese relations.
After Germany had to cede most of its Pacific and Asian possessions to Japan and with an intensifying Sino-German cooperation, relations between Berlin and Tokyo were nearly dead. Under the initiative of Wilhelm Solf, who served as German ambassador to Japan from 1920 to 1928, cultural exchange was strengthened again. A cultural agreement was signed in 1926 that led to the re-establishment of the "German-Japanese Society" (1926), the founding of the "Japan Institute" in Berlin (1926), the establishment of the "Japanese-German Cultural Society" in Tokyo (1927), and later also the incorporation of the "Japanese-German Research Institute" in Kyoto (1934). Both, France and Germany, were also very attractive for Japanese wanting to study abroad, as both countries kept their currencies undervalued in the 1920s. In fact, many of the men who emerged as leaders of the Pan-Asia movement in Japan in the 1930s studied at German universities in the 1920s, which led the Japanese historian Hotta Eri to note there was a strong German influence on the discourse of Japanese Pan-Asianism. Not only did this happen against Japanese objections, but it also caused the original complaints from China, and not those from Japan, to eventually motivate Berlin's change of attitude.
In late 1933-early 1934, another strain was placed on German-Japanese relations when the new German ambassador to Japan and outspoken proponent of German-Japanese partnership, Herbert von Dirksen, backed the appointment of Ferdinand Heye, a member of the Nazi Party and disreputable businessman, the Special German Trade Commissioner for Japan's puppet state Manchukuo in northern China. Berlin's interaction with Manchukuo was delicate, as its official diplomatic recognition by Germany was sought after by Japan, but would greatly damage Sino-German relations. Hitler's interest to keep China as a partner for the time being became obvious, when he disavowed Heye, who had falsely promised German recognition of Manchukuo in order to monopolize German trading in the region under his name. In the summer of 1935, Joachim von Ribbentrop, a German foreign policy official operating independently from the Auswärtiges Amt, together with his friend, the Japanese military attaché to Germany, General Hiroshi Ōshima, planned to relieve Germany of its China-or-Japan-dilemma by promoting an anti-Communist alliance that would unite all three countries together. However, the Auswärtiges Amt under Konstantin von Neurath vetoed this approach, as it deemed trade relations with China too important to be risked by a pact that Chiang Kai-shek was unlikely to join.
Around the same time, von Rippentrop negotiated the Anglo-German Naval Agreement, which caused a temporary deterioration of German-Japanese relations when it was signed in June 1935. At the time, many Japanese politicians, including Admiral Isoroku Yamamoto (who was an outspoken critic of an alliance with Nazi Germany), were shocked by what was seen as Germany attempting to create an alliance with Great Britain. Nevertheless, the leaders of the military clique then in control in Tokyo concluded that it was a ruse designed to buy the Germans time to match the Royal Navy. After all, Hitler had already laid down his plans in Mein Kampf, in which he identified Britain as a potential ally but also defined Japan as a target of "international Jewry", and thus a nation which Germany could potentially form an alliance with:
Consolidation of cooperation
thumb|Japanese ambassador [[Kintomo Mushakoji and foreign minister of Nazi Germany Joachim von Ribbentrop sign the Anti-Comintern Pact in 1936.]]
Tokyo's military leaders proceeded to devise plans assuring the Empire's supply with resources by eventually creating a "Greater East Asia Co-Prosperity Sphere". In general, further expansion was envisioned – either northwards, attacking the Soviet Union, a plan which was called Hokushin-ron, or by seizing French, Dutch and/or British colonies to the south, a concept dubbed Nanshin-ron. Hitler, on the other hand, never desisted from his plan to conquer new territories in Eastern Europe for Lebensraum; thus, conflicts with Poland and later with the Soviet Union seemed inevitable.
The first legal consolidation of German-Japanese mutual interests occurred in 1936, when the two countries signed the Anti-Comintern Pact, which was directed against the Communist International (Comintern) in general and the Soviet Union in particular. After the signing, Nazi Germany's government also included the Japanese people in their concept of "honorary Aryans". Yasuhito, Prince Chichibu then attended the 1937 Nuremberg Rally in Germany and met Adolf Hitler, with whom he tried to boost personal relations. Fascist Italy, led by Benito Mussolini joined the Anti-Comintern Pact the same year, thereby taking the first steps towards the formation of the so-called Axis between Rome, Berlin, and Tokyo.
Originally, Germany had a very close relationship with the Chinese nationalist government, even providing military aid and assistance to the Republic of China. Relations soured after the outbreak of the Second Sino-Japanese War on 7 July 1937, and when China shortly thereafter concluded the Sino-Soviet Non-Aggression Pact with the Soviet Union. Notwithstanding the superior Sino-German economic relationship, Hitler concluded that Japan would be a more reliable geostrategic partner and chose to end his alliance with the Chinese as the price of gaining an alignment with the more modern and militarily powerful Japan. In a May 1938 address to the Reichstag, Hitler announced German recognition of Japan's puppet state Manchukuo and renounced the German claims to the former colonies in the Pacific now held by the Japanese Empire. Hitler ordered the end of arm shipments to China, as well as the recall of all German officers attached to the Chinese Army.
The relations between Japan and Germany continued to grow closer during the late 1930s and several cultural exchanges took place, albeit motivated by political and propaganda reasons. A focus was put on youth exchanges, and numerous mutual visits were conducted; for instance, in late 1938, the ship Gneisenau carried a delegation of 30 members of the Hitler Youth to Tokyo for a study visit. In 1938, representative measures for embracing the German-Japanese partnership were sought and the construction of a new Japanese embassy building in Berlin was started. After the preceding embassy had to give way to Hitler's and Albert Speer's plans of re-modeling Berlin to the world capital city of Germania, a new and more pompous building was erected in a newly established diplomatic district next to the Tiergarten. It was conceived by Ludwig Moshamer under the supervision of Speer and was placed opposite the Italian embassy, thereby bestowing an architectural emphasis on the Rome-Berlin-Tokyo axis.
<gallery class="center">
File:Hitlerjugend Nijūbashi Edo Castle Hirohito Emperor Shōwa 1938.jpg|Hitlerjugend in Nijūbashi Edo Castle holding a symbolic greeting ceremony for Emperor Shōwa
File:Hitlerjugend meeting with Japanese leaders 1938.jpg|The Hitlerjugend meeting with Japanese leader Prince Fumimaro Konoe, August 1938
File:Japanese young ladies stage show for Hitlerjugend 1938.jpg|Female members of the Nichigeki dancing team welcoming the Hitlerjugend at Nichigeki Music Hall in Tokyo
File:Hitlerjugend dinner at German embassy August 16, 1938.jpg|Hitlerjugend having dinner at the German embassy in Tokyo
</gallery>
Although tentative plans for a joint German-Japanese approach against the USSR were hinted on in the 1936 Anti-Comintern Pact, the years 1938 and 1939 were already decisive for Japan's decision to not expand northward, i.e., the Hokushin-ron-inspired Kantokuen-plans against the USSR were shelved to embrace a southern expansion instead. The Empire decisively lost two border fights against the Soviets, the Battles of Lake Khasan and Khalkin Gol, thereby convincing itself that the Imperial Japanese Army, lacking heavy tanks and the like, would be in no position to challenge the Soviet Army at that time. Nevertheless, Hitler's anti-Soviet sentiment soon led to further rapprochements with Japan, since he still believed that Japan would join Germany in a future war against the Soviet Union, either actively by invading southeast Siberia, or passively by binding large parts of the Red Army, which was fearing an attack of Japan's Kwantung Army in Manchukuo, numbering ca. 700,000 men as of the late 1930s. – led to a temporary cooperation with the Soviets in the Molotov–Ribbentrop Pact, which was signed in August 1939. Neither Japan nor Italy had been informed beforehand of Germany's pact with the Soviets, demonstrating the constant subliminal mistrust between Nazi Germany and its partners. After all, the pact not only stipulated the division of Poland and Baltic states between both signatories in a secret protocol, but also rendered the Anti-Comintern Pact more or less irrelevant. In order to remove the strain that Hitler's move had put on German–Japanese relations, the "Agreement for Cultural Cooperation between Japan and Germany" was signed in November 1939, only a few weeks after Germany and the Soviet Union had concluded their invasion of Poland and Great Britain and France declared war on Germany.
thumb|right|German Embassy in Tokyo
Over the following year, Japan also proceeded with its expansion plans. The Invasion of northern French Indochina on 22 September 1940 (which by then was controlled by the collaborating government of Vichy France), and Japan's ongoing bloody conflict with China, put a severe strain on Japan–United States relations. On 26 July 1940, the United States had passed the Export Control Act, cutting oil, iron and steel exports to Japan. This containment policy was Washington's warning to Japan that any further military expansion would result in further sanctions. However, such US moves were interpreted by Japan's militaristic leaders as signals that they needed to take radical measures to improve the Empire's situation, thereby driving Japan closer to Germany.
Formation of the Axis
With Nazi Germany not only having conquered most of continental Europe including France, but also maintaining the impression of a Britain facing imminent defeat, Tokyo interpreted the situation in Europe as proof of a fundamental and fatal weakness in western democracies. Japan's leadership concluded that the current state of affairs had to be exploited increased Berlin's interest in a stronger alliance with Tokyo. German foreign minister Joachim von Ribbentrop was sent to negotiate a new treaty with Japan, whose relationships with Germany and Italy, the three soon to be called "Axis powers", were cemented with the Tripartite Pact of 27 September 1940.
The purpose of the Pact, directed against an unnamed power presumed to be the United States, was to deter that power from supporting Britain, thereby not only strengthening Germany's and Italy's cause in the North African Campaign and the Mediterranean theatre, but also weakening British colonies in South-East Asia in advance of a Japanese invasion. The treaty stated that the three countries would respect each other's "leadership" in their respective spheres of influence, and would assist each other if attacked by an outside party. However, already-ongoing conflicts, as of the signing of the Pact, were explicitly excluded. With this defensive terminology, aggression on the part of a member state toward a non-member state would result in no obligations under the Pact. These limitations can be interpreted as a symptom of the German-Japanese relations of that time being driven by mutual self-interest, underpinned by the shared militarist, expansionist and nationalistic ideologies of their respective governments.
thumb|upright|The Japanese embassy in Berlin, clad in the banners of the three signatories of the Tripartite Pact in September 1940
Another decisive limitation in the German-Japanese alliance were the fundamental differences between the two nation's policies towards Jews. With Nazi Germany's well-known attitude being extreme Antisemitism, Japan refrained from adopting any similar posture. On 31 December 1940, Japanese foreign minister Yōsuke Matsuoka, a strong proponent of the Tripartite Pact, told a group of Jewish businessmen:
On a similar note, both countries would continue to conceal any war crimes committed by the other side for the remainder of the war. The Holocaust was systematically concealed by the leadership in Tokyo, just as Japanese war crimes, e.g. the situation in China, were kept secret from the German public. An example would be the atrocities committed by the Japanese Army in Nanking in 1937, which were denounced by German industrialist John Rabe. Subsequently, the German leadership ordered Rabe back to Berlin, confiscating all his reports and prohibiting any further discussion of the topic.
Nevertheless, after the signing of the Tripartite Pact, mutual visits of political and military nature increased. After German ace and parachute expert Ernst Udet visited Japan in 1939 to inspect the Japanese aerial forces, reporting to Hermann Göring that "Japanese flyers, though brave and willing, are no sky-beaters", General Tomoyuki Yamashita was given the job of reorganizing the Japanese Air Arm in late 1940. For this purpose, Yamashita arrived in Berlin in January 1941, staying almost six months. He inspected the broken Maginot Line and German fortifications on the French coast, watched German flyers in training, and even flew in a raid over Britain after decorating Hermann Göring, head of the German Luftwaffe, with the Japanese "Grand Cordon of the Rising Sun". General Yamashita also met and talked with Hitler, on whom he commented,
According to Yamashita, Hitler promised to remember Japan in his will, by instructing the Germans "to bind themselves eternally to the Japanese spirit."
After reading the captured documents, on 7 January 1941 Japanese Admiral Yamamoto wrote to the Naval Minister asking whether, if Japan knocked out America, the remaining British and Dutch forces would be suitably weakened for the Japanese to deliver a deathblow. Thereby, Nanshin-ron, the concept of the Japanese Navy conducting a southern campaign quickly matured and gained further proponents.
Stalling coordination of joint war plans
thumb|Japanese foreign minister [[Yōsuke Matsuoka visits Adolf Hitler in Berlin in March 1941]]
Hitler, on the other hand, was concluding the preparations for "Operation Barbarossa", the invasion of the Soviet Union. In order to directly or indirectly support his imminent eastward strike, the Führer had repeatedly suggested to Japan that it reconsider plans for an attack on the Soviet Far East throughout 1940 and 1941. In February 1941, as a result of Hitler's insistence, General Oshima returned to Berlin as ambassador. On 5 March 1941, Wilhelm Keitel, chief of OKW issued "Basic Order Number 24 regarding Collaboration with Japan":
thumb|Matsuoka with [[Generalfeldmarschall Wilhelm Keitel (centre) and ambassador Heinrich Georg Stahmer (right) at a reception in the Japanese embassy in Berlin on 29 March 1941]]
On 18 March 1941, at a conference attended by Hitler, Alfred Jodl, Wilhelm Keitel and Erich Raeder, Admiral Raeder stated:
In talks involving Hitler, his foreign minister Joachim von Ribbentrop, his Japanese counterpart at that time, Yōsuke Matsuoka, as well as Berlin's and Tokyo's respective ambassadors, Eugen Ott and Hiroshi Ōshima, the German side then broadly hinted at, but never openly asked for, either invading the Soviet Union from the east or attacking Britain's colonies in South-East Asia, thereby preoccupying and diverting the British Empire away from Europe and thus somewhat covering Germany's back. the Soviet–Japanese Neutrality Pact was signed in Moscow on 13 April 1941 by Matsuoka on his return trip from a visit to Berlin. Joseph Stalin had little faith in Japan's commitment to neutrality, but he felt that the pact was important for its political symbolism, to reinforce a public affection for Germany. Hitler, who was not informed in advance by the Japanese and considering the pact a ruse to stall, misinterpreted the diplomatic situation and thought that his attack on the USSR would bring a tremendous relief for Japan in East Asia and thereby a much stronger threat to American activities through Japanese interventions.
From Japan's point of view, the attack on Russia very nearly ruptured the Tripartite Pact, since the Empire had been depending on Germany to help in maintaining good relations with Moscow so as to preclude any threat from Siberia. Prime Minister Fumimaro Konoe felt betrayed because the Germans clearly trusted their Axis allies too little to warn them about Barbarossa, even though he had feared the worst since receiving an April report from Ōshima in Berlin that "a Soviet-German war might break out in the near future". Foreign minister Matsuoka on the other hand earnestly tried to convince the Emperor, the cabinet, as well as the army staff of the imminent attack on the Soviet Union. However, his colleagues—regarding him as "Hitler's office boy" by now—rejected any such proposal and pointed out the fact that the Japanese army, with its light and medium tanks, had no intention of taking on Soviet tanks and aircraft until they could be certain that the Wehrmacht had smashed the Red Army to the brink of defeat.
Subsequently, Konoe removed Matsuoka from his cabinet and stepped up Japan's negotiations with the US again, which still failed over the China and Indochina issues, however, and the American demand to Japan to withdraw from the Tripartite Pact in anticipation of any settlement. Without any perspective with respect to Washington, Matsuoka felt that his government had to reassure Germany of its loyalty to the pact. In Berlin, Ōshima was ordered to convey to the German foreign minister Ribbentrop that the "Japanese government have decided to secure 'points d'appui' in French Indochina [i.e., also occupy its southern half] to enable further to strengthen her pressure on Great Britain and the United States of America", and to present this as a "valuable contribution to the common front" by promising that "We Japanese are not going to sit on the fence while you Germans fight the Russians." Unknown to Japan and Germany, however, Richard Sorge, a Soviet spy disguised as a German journalist working for Eugen Ott, the German ambassador in Tokyo, advised the Red Army on 14 September 1941, that the Japanese were not going to attack the Soviet Union until:
- Moscow was captured
- the size of the Kwantung Army was three times that of the Soviet Union's Far Eastern forces
- a civil war had started in Siberia.
Toward the end of September 1941, Sorge transmitted information that Japan would not initiate hostilities against the USSR in the East, thereby freeing Red Army divisions stationed in Siberia for the defence of Moscow. In October 1941 Sorge was unmasked and arrested by the Japanese. Apparently, he was entirely trusted by the German ambassador Eugen Ott, and was allowed access to top secret cables from Berlin in the embassy in Tokyo. Eventually, this involvement would lead to Heinrich Georg Stahmer replacing Ott in January 1943. Sorge on the other hand would be executed in November 1944 and elevated to a national hero in the Soviet Union.
Japan enters World War II
In September 1941, Japan began its southward expansion by expanding its military presence to southern Indochina ("securing 'points d'appui'") responded by placing a complete oil embargo on the Japanese Empire. As a result, Japan was essentially forced to choose between abandoning its ambitions in South-East Asia and its prosecution of the war against China, or seizing the natural resources it needed by force. The Japanese military did not consider the former an option as attacking Soviet Russia instead of expanding into South Asia had become a more and more unpopular choice since Japan's humiliating defeat in 1939 at the Battle of Khalkin Gol against General Georgy Zhukov amongst others and the final rejection of any near-term action in Siberia shortly after Germany began its invasion of the USSR. Moreover, many officers considered America's oil embargo an unspoken declaration of war. With the harsh oil sanctions imposed by the United States, the Japanese leadership was now even more determined to remain in China. Germany had refused to sell Japan the blueprints to make synthetic fuel, so Japan's only hope for oil was to invade the Dutch East Indies, which would result in war with the United States and Britain. To succeed the Japanese had to neutralize the powerful United States Pacific Fleet, so they could prevent it from interfering with future Japanese movements in South-East Asia and negotiate peace terms from a strong hand. Hitler and Ribbentrop agreed that Germany would almost certainly declare war when the Japanese first informed them of their intention to go to war with the United States on 17 November 1941.
On 25 November 1941, Germany tried to further solidify the alliance against Soviet Russia by officially reviving the Anti-Comintern Pact of 1936, now joined by additional signatories, Hungary and Romania. However, for several reasons including logistics and Soviet defenses being reinforced by East Siberian divisions, Germany's offensive on Moscow ground to a halt with the onset of the Russian winter in November and December 1941. In the face of his failing Blitzkrieg tactics, Hitler's confidence in a successful and swift conclusion of the war diminished, especially with a US-supported Britain being a constant threat in the Reich's western front. Furthermore, it was evident that the "neutrality" which the US had superficially maintained to that point would soon change to an open and unlimited support of Britain against Germany. Hitler thus welcomed Japan's sudden entry into the war with its air raid on the American naval base at Pearl Harbor on 7 December 1941 and its subsequent declaration of war on the United States and Britain, just two days after the Soviet Union started to push the Germans away from Moscow with a successful counter-offensive led by General Zhukov, who had already defeated the Japanese at Khalkhin Gol in 1939. Upon learning of Japan's successful attack, Hitler even became euphoric, stating: "With such a capable ally we cannot lose this war." Preceding Japan's attack were numerous communiqués between Berlin and Tokyo. The respective ambassadors Ott and Ōshima tried to draft an amendment to the Tripartite Pact, in which Germany, Japan and Italy should pledge each other's allegiance in the case one signatory is attacked by – or attacks – the United States. Although the protocol was finished in time, it would not be formally signed by Germany until four days after the raid on Pearl Harbor. Also among the communiqués was another definitive Japanese rejection of any war plans against Russia: