On October 19, 1948, some soldiers of the 14th Regiment of the South Korean National Defense Guard stationed in Yeosu rose up in an armed uprising. The trigger was the Jeju 4.3 Incident. Following the Jeju 4.3 uprising against South Korea's separate elections, the newly formed South Korean government ordered troops stationed in Yeosu to be dispatched as reinforcements to suppress the uprising in Jeju. Some soldiers of the 14th Regiment refused this order and staged an armed uprising, quickly occupying six counties across eastern South Jeolla Province. This became known as the Yeosu-Suncheon October 19th Incident, commonly called the "Yeosu-Suncheon Incident."
The government dispatched suppression forces and brought the situation under control within about a week, but the process saw a massive civilian massacre. The exact death toll remains undetermined even today, with estimates ranging between 2,000 and 5,000 people. Near Manseongri Beach, known for its black sand, there is a site called "Hyeongjemyo" (Brothers' Tomb), built to commemorate victims whose identities could never be confirmed. On January 3, 1949, village residents who had been detained at a nearby school on suspicion of involvement in the incident were massacred without any trial whatsoever; recorded as between 123 and 125 people depending on the source, they were buried together in the Brothers' Tomb. Today, Manseongri draws crowds of summer vacationers who come to walk on its black sand. The fact that people whose names were never even confirmed lie buried beneath that sand is not something you'd learn from looking at the surface of the beach alone.