The videos are difficult to find under GE Hong. I watch his stuff a lot - great admirer - so I know whom to look for. Here is a link to a mortice and tenon demo...
https://www.youtube.com/watch?v=LNzz...H1fG1L&index=2
This is the second of three videos, and he takes a long time to get to the chopping stage as he is in real time and preparing the timber first. Go to the 16 minute mark if you want to go directly to chopping.
His demo is very different to that of Peter Follansbee, who has the advantage of chopping against a glass wall. That adds an artificial aid in keeping the chisel aligned. Ge Hong approaches this differently ..
Regards from Perth
Derek