Obverse
日本 - Japan
支那 - China
Reverse
支那事変 - China Incident
戦揵記念 - Victory Commemorative
昭和十二年七月七日 - July, 7, 1937
盧溝橋事件 - Marco Polo Bridge Incident
The Marco Polo Bridge incident, also known as the Lugou Bridge Incident or the July 7 incident, was a battle during July 1937 in the district of Beijing between China's National Revolutionary Army and the Imperial Japanese Army. Since the Japanese invasion of Manchuria in 1931, there had been many small incidents along the rail line connecting Beijing with the port of Tianjin, but all had subsided. In this incident, a Japanese soldier was temporarily absent from his unit opposite Wanping, and his commander demanded to enter the town to search for him. Although the Japanese soldier had already returned to his lines, claiming to have suffered from stomachache, Japanese forces continued mobilizing, deploying reinforcements to surround Wanping. A shot of unknown origin was fired, and both sides began to fire on each other. The Marco Polo Bridge incident is generally regarded as the start of the Second Sino-Japanese War, and the Pacific theatre of World War II.
Another example.