When Chen Wangting created Tai Chi in the 17th century, he mapped the 8 Trigrams of the I Ching directly onto Tai Chi's 8 fundamental energies, and the 5 Elements onto the 5 directional steps. Together: 13 Postures.
But this isn't mere symbolism. In traditional Chinese thought, the I Ching is a model of how change works — reality is not made of fixed things, but of patterns of change.
This is identical to Tai Chi's underlying logic: not fixed techniques, but principles for navigating change. The opponent changes, the environment changes, your own state changes.
The practitioner who has internalized the 13 Postures doesn't respond to situations — they respond to the pattern beneath the situations.
The I Ching and Tai Chi are both maps of the same territory.