Figure: Highlighted torque stroke in the cheekbone region of Van Gogh’s *Portrait of an Old Man with a Beard* (1885).

This small brushstroke, located in the foreground of the painting, carries significant torque force and directional energy.
Despite its subtle placement, it reveals the painter's momentum, pressure, and wrist swing — forming the core movement that anchors the surrounding strokes.
In torque-matching studies, this stroke is a key reference for cross-comparisons with *The Tree Oil Painting*.