How does the look-back rule work?

The look-back rule (8-8-1) is in effect when:

• the ball is live,
• the batter-runner has touched first base, and
• the pitcher has possession and control of the ball within the pitcher's circle (both feet within the circle or on its lines).

Possession includes holding the ball in her hand or glove, under her arm or chin, or between her legs.

While it's in effect, a runner who is legitimately off her base may stop once, then must immediately return to her base or advance to the next one. Once a runner stops at a base for any reason, she's out if she leaves that base.