The 105-Man Incident (Korean:105 인 사건, hanja:百五人事件, [Paego-in sakkon]) or Seoncheon Incident (선천사건, 宣川事件) took place while Korea was under Japanese rule.
In 1911, apparently as a result of several Korean attempts in 1910 to assassinate Masatake Terauchi, the Governor-General of Korea (Chōsen Sōtoku), over 700 Koreans, many of whom were Christians, were arrested. In 1912, the Governor-General sent 122 of those arrested to the Court of Justice, and 105 of them were sentenced to imprisonment with hard labor. In the end, only six Koreans had their sentences imposed, but even they were released in 1915 after being granted amnesty.
105-Man Incident Wikipedia
The incident began in Sonchon, a coastal town in North Pyongan. On December 28, 1910, the American missionary George McCune met with Terauchi. The Japanese claimed it was an assassination attempt and arrested over 700 Koreans starting in October 1911. Lead Christian members of Sinminhoe (a Korean independence movement) were specifically targeted in the arrests, and as a result the organization was dissolved. In particular, notable activists Kim Gu, Cha Yi-seok, and Yang Jeon-baek were imprisoned. A trial of 123 defendants held on June 28, 1912, took place without evidence and confessions were extracted under torture. 105 were found to be guilty of treason and sentenced to forced labor.
Initially westerners were accepting of the incident as they had a favorable view of the Japanese and thought it might be necessary in the time of change. However, when the missionaries began feeling victimized, they distanced themselves from the Japanese government and outside pressure finally forced them to grant amnesty to the prisoners in 1915.