Protagonist: Jin Beichen, a modern college student who transmigrates into the heir of the Zhenbei General's household in the Taiji Dynasty
Golden finger: Modern knowledge of manufacturing cold weapons, basic chemistry, and management
He makes a fortune in business by fleecing corrupt officials and aristocratic clans. In government, he executes corrupt officials and treats the people well. He searches for potatoes and sweet potatoes to solve famine and food shortages, tackling one challenge after another. If Japanese pirates show up, he kills them. If the emperor wants to come after him, he'd better ask whether his special forces agree. A long sword against my pistol? I've got the advantage.
Very cool, highly recommended