Lu Mingya bound an abandoned military factory of the Republic of China that was buried deep underground. The core was not weapons, but a set of "wartime industrial technology trees." He must use captured Japanese weapons and military supplies as "raw materials" to unlock and rebuild finished product drawings and production lines. He could not create things out of thin air, he had to comply with China's industrial base and material and technology restrictions at that time. To produce a rifle, captured barrel steel is needed as raw material; to make a mortar, captured grenade tubes must be dismantled. Under the Japanese blockade and encirclement, he wanted to build this underground "seed factory" into a steel torrent manufacturing line that pierced the Sun Flag.
