This is a very interesting form indeed. Supposedly created by the somewhat mythological figure, Zhang Sanfeng (Chang San Feng), the Wudang Taiji 13 Posture Form is the form practiced at the Wudang mountain (and several other Taoist monasteries). The first two videos are of master Yuan Xiu Gang, who you can schedule a trip to study with at his website:
Wu Dang Gong Fu. He has many foreign students, and seems very friendly.
The third video is master Zhong Yun Long.
The final video is master Chen Shixing.
You can actually study this Wudang taiji in Los Angeles if you are so inclined. If anyone does, we’d love to hear about your experiences.