Introduction
In 2025, machinist Shen Yanzhi was struck by lightning in front of a machine tool. When he woke up, he had returned to Qiandao in the Southern Song Dynasty for eight years - he became Xin Qiji who had just arrived in Chuzhou. The collision of the mortise and tenon skills of a carpenter family and the knowledge of mechanical engineering allowed him to use the lever principle to improve the ramming machine, replacing the wooden parts of the Zhuge Liannu with metal gears, and the rate of fire tripled. When the emperor and the emperor were in the court, he used multi-spindle spinning wheels to revitalize Chuzhou's economy, used the "military records" system to reshape the Flying Tiger Army, and even demonstrated the "blasting method" in the quarry. The wedge-shaped mortise and tenon joints exposed among the splashing gravel were exactly the same as the machine box he made when he was twelve years old.
When the Northern Expedition horn sounded, he led the Feihu Army to tear apart the Jin soldiers' front line with multi-barreled crossbows, used pulley trebuchets to throw incendiary bombs onto the towers, and even used simplified steam principles to create "shaking thunder". At the Yellow River ferry, his prefabricated pontoon device allowed the army to walk on flat ground; under Jinan City, a human-powered boring machine broke open the city gate from the ground. When the tears of regaining his homeland soaked his shirt, the "Jiaxuan layman" with the mechanical blueprint in his hand discovered that the technological revolution he had set off had already touched the foundation of imperial power - the mountains and rivers reconstructed with gears were pushing him into a vortex of power more turbulent than the Northern Expedition.
