With a Spatial Ability, Fighting Alone to Defend the Nation's Borders

Looking for books like *Era: From the Start, I Fought My Way Through the Siheyuan and Ended Up in Beidahuang*. In the early years of the People’s Republic, the male lead is medically discharged from the Korean War and reassigned to the capital. After clashing with the children of influential families in his residential compound and seriously injuring several people, he’s sent to the frontier for development work. While guarding the border, he encounters a civilization from the future and gains access to technology...