A long-lost diary from a Chinese officer is shedding light on a lesser-known part of D-Day history. Found by urban explorers in a Hong Kong tenement, the diary details the experiences of Lam Ping-yu. He was aboard the HMS Ramillies during the invasion of Nazi-occupied France on June 6, 1944. His writings highlight the role of Chinese officers in the historic event. History enthusiasts in Hong Kong verified the diary’s authenticity, which reveals Lam’s narrow escape from torpedoes and his participation in the massive Allied operation. The discovery offers a new perspective on international cooperation during World War II.