Which novel is Su Xiu Cecilia practicing calligraphy?

It's a novel called "People in the Republic of China Change Watches for Cruisers". Su Xiu and Cecilia run a restaurant together, but the restaurant business is not good, so Su Xiu proposed to attract customers by practicing calligraphy, so Su Xiu Cecilia practiced calligraphy according to novels. Su Xiu, who was originally an ordinary person, accidentally got a double door, which enabled him to travel to and from the Republic of China at 1909. In the Republic of China 1909, the great powers were gearing up, the world was surging, and World War I was just around the corner. For the people, this is the worst time, but for Su Xiu, it is also the best time, and it is a modern time.