Republic of China: the Scrap Iron Cannon Defeated the Japanese Cannon King at the Beginning

[Hard-core military industry + suspenseful espionage + memory maze + technology flow travel] I'm just a cannon-cleaning apprentice at Fengtian Arsenal Until that day, I discovered a lot more memories that shouldn't exist The fatal flaw of the Type 41 gun, the parameters of the Japanese top-secret submarine, and even... The entire plan of the Japanese to sweep across the Northeast three years later... But what I want to know most is what the bloody ζ symbol carved on my palm before my sister disappeared means...