The story of Chongryon begins with the end of Japanese colonial rule over Korea in 1945. During the 35-year occupation from 1910 to 1945, hundreds of thousands of Koreans migrated to or were conscripted into Japan. A 1953 government survey found that 93 percent of these residents traced their origins to the southern half of the Korean peninsula. When the war ended, their nationality entered a legal limbo -- provisionally registered under the name Joseon, the old name of undivided Korea. When both South and North Korea declared independence in 1948, Joseon became a defunct nation. Those wishing to align with the South could re-register; those who supported the North could not, because Japan recognized only South Korea as the legitimate government. They retained their Joseon nationality -- citizens, in effect, of a country that no longer existed. Into this gap stepped a series of Korean organizations, each banned in turn by Japanese authorities for political activities, until Chongryon was formally established on May 25, 1955.

At its peak, Chongryon built what amounted to a self-contained society. It operated 140 ethnic Korean schools across Japan, from kindergartens to Korea University, its sole institution of higher learning. All instruction was conducted in Korean; the curriculum taught a strong pro-North Korean ideology. By the early 1970s, enrollment reached 46,000 students. Chongryon-affiliated banks and businesses provided employment and social networks outside mainstream Japanese society. The organization published the Choson Sinbo newspaper and ran cultural groups including twelve song and dance ensembles scattered from Tokyo to Hiroshima. It even operated the Man Gyong Bong 92, a passenger and cargo ferry that provided the only direct link between Japan and North Korea, connecting Niigata to Wonsan. For its members, Chongryon discouraged naturalization as Japanese citizens, intermarriage with Japanese people, and even participation in Japanese elections, viewing all of these as unacceptable assimilation.

Chongryon's role extended well beyond community services. In the 1970s and 1980s, its affiliated companies monitored the Tokyo Stock Exchange to help North Korea sell minerals at optimal prices and purchased Japanese consumer goods for re-export to Comecon countries. Annual remittances to Pyongyang were estimated at between 600 million and 1.9 billion dollars, though likely lower. The Washington Post described the organization as a "very effective sanctions-busting enterprise." In 2003, a North Korean defector told a U.S. Senate committee that more than 90 percent of parts used in North Korea's missile program were shipped from Japan aboard the Mangyongbong-92. That same year, Japanese authorities prepared espionage charges against a former senior Chongryon member whose instructions were allegedly relayed by the ferry's captain. Prime Minister Junichiro Koizumi warned that the vessel must be watched "closely lest it be used for crime." The ferry was eventually banned indefinitely following North Korea's 2006 nuclear test.

The organization that once commanded a parallel economy has been contracting for decades. School enrollment dropped from 46,000 in the early 1970s to about 10,000 by 2009, as the vast majority of Zainichi Korean families opted for mainstream Japanese schools. In Osaka, 87 percent of Korean residents attended wholly Japanese schools by 2012. The North Korean government, which funded Chongryon schools for fifty years with grants and scholarships totaling around 46 billion yen, has seen that money dry up. In 2012, Japan's Supreme Court authorized the seizure of Chongryon properties to pay off debts. The organization's headquarters building in Chiyoda was purchased in 2014 by Marunaka Holdings for 2.21 billion yen. As of 2016, the Public Security Intelligence Agency estimated Chongryon's membership at 70,000 -- a fraction of the 610,000 Korean residents in Japan who have not adopted Japanese nationality. The majority now affiliate with Mindan, the rival organization aligned with South Korea, or with neither group at all.

Today, Chongryon occupies an increasingly narrow space in Japanese society. Japanese law enforcement announced in 2019 that it would continue monitoring the organization. Zainichi Koreans who have lived in Japan for three or four generations find themselves caught between competing demands of identity and integration. A third-generation restaurant owner, an ethnic Korean, put it simply: "It's perfectly natural for Koreans who have been in Japan for several generations to be on familiar terms with North Koreans. It's certainly nothing to report to the authorities." The Chongryon building still stands in Chiyoda, still flies the North Korean flag, and still serves as the organizational center for a community defined by a division imposed eight decades ago on a peninsula an ocean away. It remains one of the strangest diplomatic artifacts of the Cold War -- an embassy that is not an embassy, for a country its host nation does not recognize, serving citizens whose nationality was assigned to them by history rather than choice.