Secret 1920 Letter by Independence Leader Kim Ga-jin Goes on Display After 106 Years

A secret letter from Joseon Minjok Daedongdan president Kim Ga-jin to military affairs chief Park Yong-man discussing plans to attack Japan’s mainland, ink on hanji paper, 28.6 x 77.9 cm, March 12, 1920. Owned by Kim’s descendants. [Photo=Dongnong Cultural Foundation]

On March 12, 1920, Joseon Minjok Daedongdan president Kim Ga-jin sent a secret letter to Park Yong-man (1881-1928), the group’s military affairs chief — a role comparable to a defense minister today. In the letter, Kim argued for an “independence war,” saying Korea should not only reclaim its territory but also open a path to strike Japan’s mainland.

“There is nothing better than to build ties with China, ally with the United States, make an agreement with the radicals, and then choose the nearest and most suitable place in Russian territory as our military’s central base, controlling Yanji and the two Gando regions. (omitted) We will be able to water our horses in Tokyo Bay.”

The letter is being shown publicly for the first time in 106 years at a special exhibition, “Joseon Minjok Daedongdan — Determined to Risk a Bloody Fight,” running through May 31 at the Museum of Modern and Contemporary History. The show is organized by the Dongnong Cultural Foundation and the Joseon Minjok Daedongdan Memorial Association.

Organizers say it is the first exhibition to focus on Joseon Minjok Daedongdan, 107 years after the group’s founding. The exhibit covers the March 1 independence movement and the group’s formation, its activities and the Daedongdan Declaration.

The first exhibition on Joseon Minjok Daedongdan in 107 years. [Photo=Yu Dae-gil]

“We will be able to water our horses in Tokyo Bay”

Joseon Minjok Daedongdan was a secret anti-Japanese independence organization formed in the wake of the March 1 movement in 1919. Because it operated as a clandestine group, few records remain. Research on Korea’s independence movement has also largely centered on the March 1 movement and the Provisional Government of the Republic of Korea, leaving Daedongdan relatively understudied. Organizers say the newly revealed letter is therefore a valuable historical source.

Kim’s family had kept the letter privately. Kim Seon-hyeon, chair of the Dongnong Cultural Foundation and Kim’s great-granddaughter, said her great-grandfather fled to the Provisional Government in Shanghai and traveled widely across China. She said that despite wars including the Korean War, her grandmother safeguarded the belongings, leaving about 600 items including the letter and calligraphy.

Kim Seon-hyeon, chair of the Dongnong Cultural Foundation, speaks at a media briefing ahead of the special exhibition at the Museum of Modern and Contemporary History in Seoul’s Gangbuk district on Feb. 27, 2026. [Photo=Yu Dae-gil]

The letter came to light during preparations for a 2024 calligraphy exhibition on Kim at the Seoul Arts Center, titled “Baegun Seogyeong.” Kim Seon-hyeon said the team transcribed the cursive text into a more readable script, confirming the existence of the secret letter and deciding to disclose it now.

Kim wrote to Park at a time of internal rifts within the Provisional Government in Shanghai. Independence activists clashed over strategy — war, diplomacy and training — and over whether to maintain the Provisional Government. Ahn Chang-ho and Yeo Un-hyeong backed keeping it while pursuing partial reforms. Shin Chae-ho and Park argued for dissolving it and establishing a new independence government, emphasizing armed struggle. Syngman Rhee and others also argued for maintaining the Provisional Government.

Kim believed independence could be achieved through armed struggle, and he was appointed an adviser to the Bukro Military Administration Office under Gen. Kim Jwa-jin. Organizers say the letter is an important document showing Kim’s resolve to pursue an independence war.

In the letter, Kim invoked the sound of a drum to press the need to advance.

“With the drum sounded once, we can strike the cunning Japanese enemy’s solid armor and sharp weapons; with the drum sounded twice, we can recover our land; with the drum sounded three times, we will be able to water our horses in Tokyo Bay.”

Dreaming of a world without discrimination

True to its name, Daedong — meaning “great unity” — the group envisioned a society without discrimination. It argued that Koreans should unite across status and class to achieve independence, world peace and a “Daedong society.” Its membership spanned social groups, including Prince Uichin Yi Kang (1877-1955), described as the only royal family member to join the independence movement, as well as Kim Ga-jin and others including Jeon Hyeop, Choi Ik-hwan, Baek Cho-wol and Lee Sin-ae. It also included teachers, students, workers, merchants and others.

The original handwritten Daedongdan Declaration written by Kim Ga-jin, pen on paper, 20.9 x 16.31 cm, 1919. Owned by Kim’s descendants. [Photo=Dongnong Cultural Foundation]

After the March 1 movement, the group elevated Kim as president and set up core bodies including administrative, foreign affairs, finance and military functions, forming an organization comparable to a government. It actively cooperated with the Provisional Government and divided responsibilities.

It communicated with the Provisional Government through the Yeontongje network, ran a secret printing operation and led anti-Japanese information activities. The nationwide network was used to share news of the Provisional Government inside Korea and raise military funds, functioning like a communications web.

The group also supported the exile of royal family members and former Korean Empire officials, raised funds and held current-affairs lectures for Koreans in Shanghai. It issued the Daedongdan Declaration — described as a second March 1 declaration — explored plans to attack Japan’s mainland and shared the Provisional Government’s work in military, diplomacy, finance, communications and propaganda. It also pushed for Prince Uichin Yi Kang’s flight to Shanghai, aiming to counter Japan’s claim that Emperor Gojong had legally transferred the country to Japan, a move organizers said strengthened the legitimacy and symbolism of the independence struggle.

Independence curator Lee Dong-guk (a former Gyeonggi Provincial Museum director) and Kim Seon-hyeon view the original Daedongdan Declaration at the special exhibition in Seoul on Feb. 27, 2026. [Photo=Yu Dae-gil]

The exhibition also features the original Daedongdan Declaration written by Kim, also preserved by his descendants. The group announced the declaration in Jongno on Nov. 28, 1919, during what the article describes as a second independence demonstration, led by figures including Jeong Gyu-sik, Lee Sin-ae and Park Jeong-seon. Kim, then in exile in Shanghai, drafted the text in his own hand and sent it to Gyeongseong through the Yeontongje network.

As with the March 1 declaration, the Daedongdan Declaration centered on 33 people, but it is noted as the only case in which participants from across social strata joined nationwide. The article says it rejected discrimination by gender and status.

The declaration denounced Japanese abuses and stated, “We now declare that we are determined to risk a bloody fight with the greatest sincerity and the greatest effort until the last person and the last moment,” underscoring its commitment to independence. The exhibition also includes a first-trial ruling from the Gyeongseong District Court written in June 1920 on the “Daedongdan incident,” and an original handwritten “current-affairs lecture” document by Kim.

“Joseon Minjok Daedongdan is an important anti-Japanese independence organization, but little is known about it,” Kim Seon-hyeon said. “I hope this exhibition will help many people reflect on the spirit of Daedongdan.”

An expert forum titled “Daedong Thought and Society” will be held April 24 in the museum’s seminar room. Participants include Han Hong-gu, a chair professor at Sungkonghoe University, Kim Dong-hwan, a research fellow at the Institute of Korean Studies, and Lim Gyeong-seok, a professor at Sungkyunkwan University. Admission is free.

* This article has been translated by AI.

Yoon Juhye