The Handbook of Tang Dynasty Price Collapse

Chen Shi accidentally opens a passageway in the old house his grandfather left behind. On the other side lies the Tang Dynasty, in the early years of the Zhenguan era. He brings a lighter, and the West Market goes wild. He brings glass mirrors, and the bronze-mirror trade goes wild. Later, he discovers that the passageway has a quota and charges taxes. So he switches tactics: He brings formulas, blueprints, and manufacturing techniques. The passageway can only tax what he carries on paper, but he crashes prices across entire industries. The West Market has no idea that the first industry to collapse is only the beginning.