Datang Started with Water Turning into Ice

Shen Feng traveled to Chang'an City in the Tang Dynasty, the first year of Zhenguan. Activate the check-in system and get a lucky draw every seven days. After signing in for the first time, he received saltpeter and used it to make ice, which became a hit in Chang'an City and became a wealthy businessman. After signing in for the second time, I received poems from literati, and accidentally became as famous as a great Confucian. Signing in for the third time and getting a telescope made Li Shimin know that the earth is just a ball in the universe. There are more and more things signed in, from steelmaking to munitions. Until one day, the protagonist draws a 10,000-ton ship.