[hawk65]

The 2008 NFHS Rules Book and Case Book state:

Rule 2-45: PITCHER’S 16-FOOT CIRCLE (F.P.) The 16-foot circle is used for the look-back rule. A pitcher is in the 16-foot circle when both feet are within or partially within the line. The feet may touch the line and extend outside the line. (1-1-2d)

Rule 2-47 "PLAY BALL," MAKE A PLAY, INITIAL PLAY
ART. 2 . . . Make a Play.
a. Any action by the pitcher intended to cause a reaction from the runner(s) as it pertains to the look-back rule (F.P.).

Rule 8-7 (F.P.) LOOK-BACK RULE
ART. 1 . . . The look-back rule will be in effect when the ball is live, the batter-runner has touched first base or has been declared out, and the pitcher has possession of the ball within the pitcher's circle. (2-45)

8.7.1 SITUATION A: R1 is on third base when B2 receives ball four. R1 comes off the base on the pitch. The catcher throws the ball directly back to the pitcher in the 16-foot circle. Can R1 remain off third base until B2 has reached first? RULING: Yes. The look-back rule does not go into effect until the batter-runner has touched first base and the pitcher has possession of the ball in the 16-foot circle. At that time, all runners on base must immediately move forward or return to their base.

8.7.1 SITUATION C: Just after ball four is called on B2 and she is on her way to first base, R1 dances off third base and is moving back and forth between third and home. F2 throws the ball immediately back to F1 in the 16-foot circle. RULING: R1 is not restricted and governed by the look-back rule until B2 reaches first base.

They state when the "look-back rule" is in effect but where does it define the "look-back rule" in NFHS softball?