Introduction to the Beiyang Navy History Exhibition Hall: On September 17, 1894, the main force of the Beiyang Navy, headed by "Dingyuan" and "Zhenyuan", fought a decisive battle with the main force of the Japanese Navy's Combined Fleet in the Dadonggou waters of the Yellow Sea. The "Dingyuan" ship was hit by 159 bullets, and the "Zhenyuan" ship was hit by 220 bullets. The craters on the armor and turret armor of the "Ding" and "Zhen" ships did not exceed 102 mm, which shows the tenacity of the two ships. vitality.