Yung - Hwui , a Chinese law book , specified that in order for a husband to divorce must present a document giving the reasons for the action , all letters must be in his handwriting .
If unable to write , Yung - Hwui must sign with Yung - Hwui 's fingerprints .
Yung - Hwui , a Chinese law book , specified that in order for a husband to divorce must present a document giving the reasons for the action , all letters must be in his handwriting and if unable to write , he must sign with his fingerprints .