Hi littlepanda!
As I know it is not you, is it? I hope not, because I don't want to harm you any way!
I am sorry to say but it is actually totally wrong.
He is using a "backward arch" yes, but still his weight is supported by his knees, and not by the hip joints. The movement itself is also done by the knees and not by the hips.
Even his leg positions are wrong. That is why his all weightshift is wrong.
This way he will destroy his knees, just as lots of other taiji guy did.
And please don't label this video as "Weight shifting in chen taiji", because it is not the way we shift weight in chen taiji! It is the way this guy shift weight...
Sorry!
Cheers,
Örs