The following, were I believe, originally formulated by Ben Lo. The commentary on the five principles, I'm guessing, was authored by the host site cited at the end of email.
I have often present these in w/shops as the essential focus of practice. Having grasped these five principles in practice we can then further our understanding of the many T'ai Chi Ch'uan principles. Whilst the following five principles may read relatively easy, I have found them not so easy to maintain in practice....still trying. - JH
Five Basic Principles of T’ai Chi
John Hartley, Founder and Principal Instructor of Inner Health School of Taijiquan, Adelaide