What does the sky mean in a perpetual calendar?

Hello, after my research, the correct solution of the heavenly prison in Wanli period you mentioned should be Yingtian prison.

After the Five Dynasties, in 937, in the second year of Emperor Gaozu Tianfu, the Southern Tang Dynasty was founded, with Jinling as its capital, and Jinling House was changed to jiangning house. In the eighth year of Kaibao in Song Taizu (975), jiangning house was changed to Shengzhou Prefecture; In the second year of Tianxi (10 18), it was upgraded to jiangning house. In the first year of Emperor Gaozong Jianyan in the Southern Song Dynasty (1 127), jiangning house was changed to Jiankang House, which made Shaoxing its capital for 8 years (1 138) and officially established Lin 'an House (now Hangzhou, Zhejiang). In the second year of Jian 'an (1329), Kangjian was rebuilt as.

In the early Ming Dynasty, Qing Ji Road was changed to Yingtianfu and the capital.

The Yingtian Prison you mentioned was Tianzihao Prison in Nanjing at that time. The diversity of domestic criminal law is amazing.