Remember When Poland Declared War On Japan- And It Lasted 16 Years?

Photo Credit: Interim Archives/ Getty Images)

Although Japan allied itself with Nazi Germany and Italy during the Second World War, it did not support the Nazi invasion of Poland in 1939. In fact, the Empire of Japan actively supported the Polish government-in-exile at the start of the Second World War, until 1941 when Poland sent a declaration of war to Japan. Surprisingly, this little-known war lasted for 16 years. Here, we take a look at Japan and Poland’s unique relationship.

A Japanese military unit stands in fighting formation with rifles raised during the Russo-Japanese War. (Photo Credit: Hulton Archive/ Getty Images)
A Japanese military unit stands in fighting formation with rifles raised during the Russo-Japanese War. (Photo Credit: Hulton Archive/ Getty Images)

Cooperation between the Japanese and Poles dates back to the Russo-Japanese War at the start of the twentieth century. During this conflict, Polish independence activists cooperated with Japanese intelligence, providing them with information about the movement of Russian troops. In fact, despite Poland not yet being recognized as an independent country, it was deemed a “Samurai Nation” by Japanese author Nitobe Inazō in his 1904 book Bushido: The Soul of Japan. 

After the First World War, Japan officially recognized Poland as an independent state. This marked the beginning of international relations between the two countries. After the First World War, Japan supported Poland’s efforts to join the League of Nations as an independent nation.

German invasion of Poland
An armored column of Third Reich forces stream into Poland, igniting the war in Europe, September 1939. (Bettmann/ Getty Images)

In 1923, the Polish military taught the Japanese Army cryptography after sending Polish military officers to Japan to teach the Japanese encryption skills. The Japanese army had been struggling to break Soviet radio signals for over a year at this point. With the help of the Poles, these signals were cracked in just a few weeks.

Despite having different allies at the start of the Second World War, the Japanese and Polish continued a strong relationship. The Japanese were in diplomatic opposition to the German invasion of Poland on September 1, 1939. The continued diplomatic and military relationship between Poland and Japan at the start of the Second World War was heavily influenced by distrusting the Germans after entering into a secret pact with the Soviet Union.

After the outbreak of the Second World War, a Polish espionage network was created at the Japanese embassy in Berlin, and Polish agents and diplomats traveled on passports provided by the Japanese.

Japanese attack on Pearl Harbor
Ford Island is seen in this aerial view during the Japanese attack on Pearl Harbor December 7, 1941 in Hawaii. The photo was taken from a Japanese plane. (Photo Credit: Getty Images)

However, this relationship changed after the Japanese attack on Pearl Harbor on December 7, 1941. Immediately following these attacks, the United Kingdom declared war on Japan along with its dominions and Allied governments in exile. These governments included Belgium, the Netherlands, the French National Liberation Committee, and eventually, Poland.

On December 11, 1941, the Polish government-in-exile reluctantly declared war on Japan. However, the Japanese government politely refused Poland’s declaration of war, making the declaration legally void. Japanese Prime Minister Hideki Tojo stated, “We do not accept Poland’s challenge. The Poles, fighting for their freedom, only declared war on us under pressure from the United Kingdom.”

Hideki Tojo 1940s
Japanese general and former prime minister Hideki Tojo circa 1940s. (Photo Credit: AFP/AFP via Getty Images)

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Despite this state of war that existed on paper, cooperation continued between Poland and Japan throughout the remainder of the Second World War. The Poles continued to give the Japanese intelligence on the USSR and Germany in exchange for passports provided by the Japanese.

This state of war existed for 16 years until it was formally dissolved in 1957 when the agreement to restore a normal relationship between the People’s Republic of Poland and Japan was signed.