Day and night,
I copy the Diamond Sutra
of Prajnaparamita.
My writing looks more and more square.
It proves that I have not gone entirely
insane, but the tree I drew
hasn’t grown a leaf.
—from “I Copy the Scriptures,” in Empty Chairs

Every month, the Chinese poet, photographer, and artist Liu Xia boards a train bound for the country’s north. Carrying food and books and escorted by four plainclothes police officers, she heads for a prison in the city of Jinzhou where her husband, the Nobel Peace Prize laureate Liu Xiaobo, is serving a sentence for subversion of state power. The ritual rarely varies: rising early to get the morning train, a short visit, and the train back.

The ride used to take six hours each way but Ms. Liu now makes it in just three—a tribute to the power and might of a state that rolls out high-speed rail lines as quickly as it snaps up those who oppose its vision of China’s future. Now fifty-five years old, Ms. Liu is one of those victims: a small, fragile woman with extremely short-cropped hair that sets off her high cheek bones and bright, wide eyes.

She has lived under strict police surveillance ever since her husband won his prize in 2010, one year into his eleven-year prison term. For more than three years, she could not see friends or even receive phone calls. Those close to her spoke of her becoming unbalanced from the pressure. When Associated Press journalists snuck past guards and knocked on her door in 2012, she trembled, cried, and said her situation was “Kafkaesque.” In 2014, people close to her reported that she was hospitalized due to heart ailments and depression.

Now friends say that she is regaining strength and devoting herself to reading and writing. While her husband is most famous for his blunt, sarcastic, and highly topical essays, Ms. Liu’s works have taken longer to become known—not surprising for an artist who cannot publish or exhibit in her home country. But her poems and artworks are emerging in their own right as…