Snap a straight 2 m chalk line to the center of the hole, or lay down an alignment stick. Draw a line on the ball too and set it on the chalk line. Square the face to the chalk and hit putts, checking that the ball's line rolls end over end without wobbling.
On video from behind, the putter face doesn't point at the chosen line at address; the ball starts off the read line within the first meter.
Frequently asked questions
What is the "Chalk line on the green" drill for?
Align the face to an objective reference
How do you do the "Chalk line on the green" drill?
Snap a straight 2 m chalk line to the center of the hole, or lay down an alignment stick. Draw a line on the ball too and set it on the chalk line. Square the face to the chalk and hit putts, checking that the ball's line rolls end over end without wobbling.
How long does the "Chalk line on the green" drill take?
About 15 minutes per session, 20 reps.
Sources
Dave Pelz — Dave Pelz's Short Game Bible
Dave Stockton (con Matthew Rudy) — Unconscious Putting