Song Dynasty's translation of banknotes

The "this" in "this arm cannot move" is a pronoun, meaning "this".

Zhu Meng (the big businessman) wore a brocade robe and told others that "Emperor Huizong often touched him with his hands" so he embroidered gold handprints on his shoulders. Another time, when he was drinking in the inner palace, Emperor Huizong personally held his arm. Zhu Meng wrapped a yellow silk cloth around his arm. When he bowed to the person, he kept his arm motionless, indicating that this arm had just been Photographed by the emperor.