Qincheng Prison
Once a prisoner enters the prison, his or her original name is no longer used. Instead, the prisoners are referred by number. The number consists of two parts, with the first two digits indicating the year the prisoner was sent to Qincheng prison, while the remaining digits are the sequential number. For example, prisoner 6299 means that the prisoner was sent to the prison in 1962, while he or she was the 99th prisoner sent to Qincheng Prison that year.