After Marrying the Princess, I Changed the World

Du Heng, a mechanical engineering junior from twenty-first-century China, awakens in the body of a fourteen-year-old orphan named Du Heng during the fifth year of the Zhenguan era in the Tang Dynasty. Stranded in a dilapidated hut outside Chang’an with no system, cheat, or superpowers, he relies on his modern scientific knowledge and engineering mindset to survive. The original owner died of neglect and poverty, leaving behind only half a mu of barren land and a tattered copy of the Qimin Yaoshu. Du Heng immediately formulates a two-year survival plan, prioritizing agricultural improvement through crop rotation, composting, and ecological farming cycles. He sharpens a rusty hoe, diverts mountain spring water, and establishes three functional zones: a plantation for drought-tolerant crops like sorghum and soybeans, a livestock area for chickens and pigs, and a workshop for food processing.

His initial efforts focus on self-sufficiency and resource gathering. He ventures into Zhongnan Mountain to collect wild vegetables, soap pods, and medicinal herbs, while also discovering a hidden wooden box left by his deceased father. The box contains household registration slips revealing his lineage as a collateral branch of the prestigious Du clan of Duling, a broken jade pendant with the character “Ling,” and a map to the Du Clan Ancestral Tomb. Rather than pursuing these mysteries immediately, Du Heng prioritizes his practical plan. He successfully cultivates his land, raises chickens, and begins experimenting with food preservation techniques such as curing meat and brewing soy sauce using fermented black beans.

The turning point arrives when Du Heng introduces stir-frying to the village, a cooking method unknown to the common people of this era. Using a custom-forged iron wok and lard, he creates dishes that astonish the locals with their aroma and taste. He takes his cured meat and stir-fried vegetables to the West Market in Chang’an, where they gain immediate popularity among both Han Chinese and foreign Hu merchants. The profits allow him to expand his operations and refine his recipes. He then paints a large mural on his courtyard wall depicting pastoral scenes infused with mechanical principles, such as pulley systems and steam power, effectively visualizing his philosophy of “gewu” or the investigation of things.

Emperor Taizong Li Shimin, intrigued by reports of a youth who combines practical mechanics with agriculture, visits Dujiawa incognito. He is impressed by Du Heng’s knowledge and humble demeanor. Du Heng declines an offer of official rank, stating that his ambition lies in spreading practical knowledge to benefit the common people rather than serving in government. The Emperor, recognizing Du Heng’s potential, grants him permission to establish a “Huimin Workshop” to teach these techniques to the public. Shortly after, Princess Changle visits Du Heng’s establishment, the “Xiaoyao Tower,” which she helps fund. She is captivated by his integrity and culinary skills, leading to a romantic subplot as she invests in his business ventures.

As Du Heng’s influence grows, he faces the challenge of scaling his agricultural and culinary innovations while navigating the complex political landscape of the Tang court. The story follows his journey from a starving orphan to a respected innovator who uses science and technology to improve the lives of ordinary citizens. His ultimate goal is to open a “Gezhi Institute” to disseminate modern knowledge, challenging the entrenched aristocratic clans and reshaping the economic and social fabric of the Zhenguan Golden Age. Through hard work, strategic planning, and the application of scientific principles, Du Heng begins to alter the course of history, one stir-fry and one crop rotation at a time.