Jesse Enkamp has recently revealed some video from his China studies that shows a form with a great deal in common with Seishan. I can only assume he was inspired by my lowly blog to share it. ;)
I'd love to see the whole form!
Update: The whole form.
Having seen this, I think the influences are apparent, but there are lots of other forms with similar movements. But you know, just as there are several versions of seisan on the tiny island of Okinawa, it could just be that on the mainland, a bigger game of telephone is being played, and different people brought different part of Seisan with them. Still, this a very interesting form, and nice to see it preserved on video.