A recent increase in anti-immigrant sentiment in Japan has led people from some religious and ethnic groups who were not born in Japan to face hostility. Hate speech has spread on social media, and some mosques have been targeted with abusive messages.

Over the past five years, the number of Muslims in Japan has nearly doubled, from 230,000 in 2019 to 420,000 at the end of 2024. Most Muslim immigrants are workers from Southeast Asia and South Asia.

All this has been unfolding amid a larger demographic change. The population of mixed-race Japanese children, known as “hafu,” or half, has also increased in Japan over the past three decades. The number of children born in Japan who have one or two non-Japanese parents reached 4.66% in 2023, up from just 1.3% in 1987.

A long-standing myth that Japan is a homogeneous society, which has often been linked to Japanese “racial purity,” has exacerbated anxieties over demographic change. This is despite the reality that Japan has its own indigenous population in the north of the archipelago, known as the Ainu, as well as generations of Japanese of ethnically Korean, Chinese and Ryukyu, or Okinawan, heritage to complicate the landscape.

Along with Japan’s falling birthrate, these immigration patterns have accelerated fears among politicians and ordinary Japanese alike about racial purity and what constitutes “Japaneseness.”

What many don’t know is that Japan has a largely forgotten and complex relationship with Islam and Muslims that predates contemporary immigration patterns. As a Japanese scholar of Islam, I have studied how Muslims perceived Japan during the 19th and early 20th centuries. In the early 20th century, the Japanese government used positive perceptions of Japan among Muslims to build alliances with Muslims across Asia as part of its geopolitical strategy.

Rumors of Japan’s conversion to Islam

Unlike much of Asia, Japan was never colonized. Instead, in the late 19th century, Japan started to build its own empire, exerting influence over Korea as well as Manchuria, an important area of modern-day China that borders Korea, Russia and Mongolia. Japan’s victory over Russia in the Russo-Japanese War of 1904-05 established it as a major world power.

For the Muslim-majority regions that had once seen themselves as centers of learning and power, European domination over parts of Asia – including South Asia and Southeast Asia, Africa and the Middle East – was seen as humiliating.

Muslim thinkers debated how to revitalize their societies and overcome colonial domination. For some Muslim intellectuals and travelers, Japan’s modernization and its victory over Russia was proof that Asian nations need not be subservient to Europe or abandon their own cultural traditions.

Japan’s victory over Russia inspired such admiration that it gave rise to an unlikely, false rumor around the time of the Russo-Japanese War: the Japanese emperor would soon convert to Islam. According to these circulating reports, the Japanese population too would also convert out of loyalty to their emperor.

These rumors may have started in India and subsequently circulated in Indonesia, then a Dutch colony. People believed that a newly Muslim Japan would lead the Muslims of Asia in anti-colonial resistance against the West.

At the time, steamships and the printing press enabled people and ideas to travel farther and faster across the globe than ever before. Newspapers in Arabic, Urdu and Persian, published in cities such as Bombay, now Mumbai, Calcutta, or Kolkata, Istanbul, London and Cairo helped in spreading religious and political ideas across the globe.

Despite this publishing boom from the 1860s to the 1920s, however, most people in South Asia, Southeast Asia and the Middle East still had little direct knowledge of Japan. That lack of firsthand knowledge made it easier for the rumors to spread and seem credible.

For many Muslim reformers, Japan represented a non-Western model of modernity. Egyptian activist and lawyer Mustafā Kāmil Pasha described Japan as the “rising sun to Egypt’s sun that has already set.” He saw Japan as an emerging global power, at a time when Egypt had fallen behind economically, militarily and intellectually.

How Japan made use of the rumors

The rumors, while untrue, did offer Japan an opportunity to position itself as an anti-colonial leader.

Japanese military intelligence seized on the potential of finding allies among the world’s Muslims. Important figures in Japanese military intelligence supported an ideological movement called Pan-Asianism. This movement sought to promote the political, cultural and economic unity of Asian peoples under Japanese leadership by stressing their common Asian heritage.

Secretive Japanese Pan-Asianist organizations cultivated alliances and met with Muslims to build networks with Muslims in China, Russia and India. Japan sought to build alliances against Russia, Great Britain and other European nations. One notable Pan-Asianist group was the Kokuryūkai, or Black Dragon Society, founded in 1901. Black Dragon Society members forged relationships with Muslim nationalists in Russia and in the Ottoman Empire in order to build a pro-Japanese network.

One of the members of the Black Dragon Society was Omar Yamaoka, born Yamaoka Kōtarō. Yamaoka was among a handful of Japanese Muslims who had converted to Islam as a political and strategic act, while remaining ideologically committed to Japanese imperialism, the Japanese emperor, and Shinto as a religion.

Japanese Muslims like Yamaoka could travel throughout Muslim majority countries without attracting unnecessary attention. They could build networks and report their findings back to the military in Japan.

Complex pasts

For decades, Japan continued with this strategy and even developed an Islam policy in the 1930s. The goal of Japan’s Islam policy, or “Kaikyō Seisaku,” was to build Japan’s sphere of influence across Asia. It fostered alliances with Muslims in China, Russia, Central Asia and the Caucuses, Southeast Asia and India as part of this policy.

Japan’s empire expanded in the decades leading up to World War II. However, it collapsed when Japan experienced a catastrophic defeat in 1945. Japan was occupied by the United States, and the emperor was stripped of his semidivine status. In the decades since then, Japan has largely adopted a pacifist stance that disavows its imperial past.

Today, amid Japan’s shrinking population and anti-immigrant sentiment, it might be jarring to remember that there once were hopes that Japan would be the anti-colonial leader of the world’s Muslims and that some of Asia’s Muslims dreamed of an Islamic Republic of Japan.

Mimi Hanaoka does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.