We've been covering some interesting stuff on-list. For me, entering into Taiji posture 1st. through correct Wuji-bu and then through Zhan Zhang (Universal Post) make sense. Wuji-bu suspends the head and gets one settled into the kwa with the back relaxed and both the Ming-men and the C7 opened with weight falling down into the earth through the centre of each foot. This is the essence of every step and transitional movement in Taijiquan. Wuji-bu gives you the basic shaping of back and shoulders as well. Raising the arms into Zhan-zhang very subtly modifies this and defines the degree to which the chest is hollowed. It is of the essence to understand that this is not something one DOES, but something that just HAPPENS when the correct alignments are in place and the tensions are released. In Zhan-zhang remember that the elbows are slightly out from the body and relaxed downwards and that the forearms help this by being slightly rotated so that you can look into the centre of your palms. Also note that the tips of the fingers of the two hands are separated by a distance of about 7" - 11" depending upon one's stature. Tracing a line from sternum to the back of forearm or wrist gives the angle of lateral power which is basic to Jin. All of this is not Taiji, but is part of the skilfull means that leads one to it.