Chinese minorities often show stylistic elements from much earlier periods in Chinese history. Here is a Yi minority chopper that is almost identical to Song shoudao that are otherwise only found in period art as depicted on Thomas Chen's website.
http://thomaschen.freewebspace.com/catalog.html
I suspect the shoudao is the originator of many choppers of similar size.
http://i77.photobucket.com/albums/j6...duation366.jpg
Josh