Home History A Second Look at the Ireizo

A Second Look at the Ireizo

Analysis by Reika Nishiyama
Text by David Yamaguchi
The North American Post

Number of residents in the Minidoka and Manzanar camps plotted by birth year every five years Data are from Ireizocom 2574 2214 individuals plotted respectively

Many books and articles in this newspaper have described how Japanese Americans fall into distinct age groups as a consequence of abrupt openings and closings of immigration. Controlling historical events here include the opening of Japan (1868), the American need for laborers after the Chinese Exclusion Act (1880), the Gentleman’s Agreement (1906), which halted male-laborer immigration, the closure of the picture-brides loophole (1920) and the cessation of immigration (1924) until immigration reform (1965). However, while JAs have been able to see and feel these age groupings in-person at extended family and community gatherings throughout their lifetimes, they have not been able to see them graphed on paper.

The posting of the Ireizo database on the internet changes the latter situation because incarceration camp residents are listed there by birth year. Accordingly, residents in the two example camps above, where Seattle and Bainbridge people were held, fall into three age groups.

The Issei, the first-wave of immigrants, formed a broad 40-year age group born from about 1870 to 1910. In turn, their Nisei children comprise a rapidly rising and falling wave from about 1910 to 1935. From about 1935, we see the start of a third wave, the Sansei “camp babies.”

In addition to there being well-defined age waves, the shape of each wave varies. The Issei wave is wide because the men arrived first, as laborers; and women arrived later; commonly as younger brides. The narrow Nisei rise and fall reflects the abrupt arrival of these women, most in their early 20s, followed by the ending of their fertility period.

The Sansei wave is artificially small because it reflects the departure of many Nisei for inland jobs. Nonetheless, its overall shape probably strongly mirrors the Nisei wave, because Nisei mainly married other Nisei.

Moreover, the strong similarity in age distributions at the two camps suggests that the age-spread of JA communities in different West-Coast regions was identical. The Manzanar camp residents were mainly from Los Angeles and Stockton, while those at Minidoka were from Washington, Oregon and Alaska.

As the exploratory graph above only plots data in five-year intervals, finer interpretation of each curve should not be made without more detailed plotting.


Reika Nishiyama is a student in the International Business Professions (IBP) program at Bellevue College. She is interning with the NAP to explore her interests in English-language journalism and Japanese Americans..

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The North American Post is a community newspaper that celebrates Japanese culture in the Greater Seattle area. Founded by 1st generation Japanese-Americans in 1902, the publication is one of the oldest minority-owned newspapers in the region. Today, with bilingual articles in English and Japanese, the publication connects readers with diverse cultural backgrounds to Seattle’s Japanese community. Our articles include local news, event calendars, restaurant reviews, Japanese cooking recipes, community interviews, and more.