Around 80 people stood before the stone monument, built in 2021 outside the Nagasaki Atomic Bomb Museum, for a moment of silence at 11:02 a.m., the exact time the bomb was dropped on 9 August 1945.
The attack killed more than 70,000 people, including many wartime Korean labourers and prisoners of war.
The Korean Atomic Bomb Victims Association says over 50,000 Koreans died in both Nagasaki and Hiroshima.
Survivors, campaigners and community leaders stressed the decades-long struggle to secure recognition and support for victims, calling the memorial a long-awaited dream fulfilled.
