Siheyuan: Raising My Soul Ring with an Entire City of Japanese Invaders

[Parallel World] After transmigrating to the capital in 1937, Zheng Weiguo awakens a Soul Ring System. Every Japanese soldier he kills increases his soul power and combat strength. He keeps a low profile in the courtyard compound and the steel mill, while hunting Japanese soldiers and collaborators everywhere, all the while matching wits with He Daqing, Yi Zhonghai, Jia Zhangshi, and the rest.