Before the War

Japanese Immigration to Hawaiʻi

In 1940, Hawaiʻi was still a territory of the United States — statehood would not be achieved until 1959. Thriving fields of sugar cane dotted the landscape of most of the Hawaiian Islands. They had been made productive and profitable with immigrant labor, first from China and then from Portugal.

The first large-scale group of immigrants from Japan arrived in Hawaiʻi in 1885, following an agreement between the Kingdom of Hawaiʻi and the Japanese government to supply laborers for the growing sugar plantation industry. At the time, the Japanese government strictly regulated overseas travel, and emigration was permitted only under official sanction.

These early migrants, known as kanyaku imin (government-sponsored contract immigrants), were recruited to work primarily on sugar plantations. Tens of thousands more followed in subsequent decades, many coming from economically disadvantaged rural areas — especially the prefectures of Hiroshima, Yamaguchi, and Kumamoto, as well as Okinawa.

In 1898, the United States annexed Hawaiʻi, and in 1900 it became a U.S. territory. Despite this political change, Japanese immigration to the islands continued into the early 20th century.

Settlement and Family Formation

Although many immigrants initially intended to return to Japan, harsh plantation conditions often limited their ability to save money, and the high cost of return travel made leaving difficult. Over time, many chose to remain in Hawaiʻi and pursue opportunities beyond plantation labor. Instead of returning home, many men chose to establish families in Hawaiʻi by arranging marriages with women in Japan through the “picture bride” system. These women traveled to Hawaiʻi to join husbands they had never met in person, helping to stabilize and grow the community.

The first-generation Japanese immigrants, the Issei, gave birth to the Nisei, the second generation, who were American-born citizens of Japanese ancestry. The majority of the soldiers of the 100th Infantry Battalion were drawn from this Nisei generation, although some were even Sansei (third generation), reflecting the deep roots of Japanese families in Hawaiʻi.

These Americans of Japanese ancestry (AJA) were raised in a multicultural environment where traditional Japanese values such as loyalty and duty to family, community, and country were blended with the American principles of freedom and democracy that they learned in public schools. Although raised in close-knit Japanese communities, they were also influenced by Native Hawaiian culture as well as the diverse customs and traditions of the many immigrant groups that had settled in Hawaiʻi.

Citizenship

Until 1924, Japanese nationality law granted citizenship through the father, meaning that many children born to Japanese fathers automatically received Japanese citizenship regardless of birthplace. In contrast, the United States granted citizenship to anyone born on U.S. soil under the 14th Amendment to the Constitution. As a result, many Japanese Americans born in Hawaiʻi before 1924 held dual citizenship in both Japan and the United States.

In 1924, the U.S. Congress passed the Immigration Act of 1924 (National Origins Act), which effectively ended immigration from Japan. That same year, Japan revised its nationality laws so that children born outside Japan would no longer automatically receive Japanese citizenship unless their birth was registered with a Japanese consulate within a limited period. The revised law also made it easier for American-born children of Japanese immigrants to renounce their Japanese citizenship. Previously, men subject to military conscription could not easily renounce their Japanese citizenship and remained liable for compulsory military service if they resided in Japan. After 1924, Nisei could renounce Japanese citizenship even during draft age, removing potential obligations to serve in the Japanese military. However, many AJAs were unaware that they held dual citizenship or did not fully understand the legal process required to renounce their Japanese nationality, and therefore remained dual citizens without realizing it.

Growth of the Japanese American Community

By 1924, approximately 110,000 people of Japanese ancestry lived in Hawaiʻi. By 1940, that number had grown to about 158,000, with roughly two-thirds of them American-born citizens.

While many Issei remained on plantations to raise their families, where conditions had gradually improved through organized labor efforts, others yearned for a life beyond the sugar cane fields, opening small businesses or working as skilled tradesmen. Like other ethnic groups who immigrated to the United States, the Issei placed a strong emphasis on education, sacrificing greatly to provide better opportunities for their children.

Despite these efforts, racial discrimination limited employment opportunities for AJAs, even those with college degrees, and barred most from positions in large Caucasian-owned companies. As a result, many turned to professions such as teaching.

Many of the young men who would later serve in the original 100th Infantry Battalion came from working-class families and left school early to help support their households. For them, completing high school, or even eighth grade, had to suffice. Although only a relatively small portion of the men had attended college, most commonly the University of Hawaiʻi, and even fewer had earned degrees , the soldiers of the 100th would perform remarkably well on Army intelligence examinations, scoring only slightly below the threshold typically required for admission to Officer Candidate School.

As these young men built their lives in Hawaiʻi, events unfolding beyond the islands were steadily drawing the United States toward global conflict.