✅ USBC Rule – Use of All Gripping Holes

USBC rules state:

If a bowling ball has drilled gripping holes, and the bowler uses that ball for delivery, then every gripping hole must be used on every delivery with that ball.

That means:

1️⃣ First ball (strike shot)

If the bowler is using a ball that has finger holes:

They must have their fingers in all of the gripping holes for the delivery.

If they don’t use the holes (ex: two-hander holding the ball by the sides but the holes exist), that is a rules violation.

2️⃣ Spare ball

The rule applies per ball, not per frame.

If the bowler switches to a different ball for the spare, they only need to use the holes on that ball.

Example:

First ball = a ball with 3 holes → he must use all 3 holes.

Spare ball = plastic ball with only 2 holes → he only needs to use the 2 holes.

3️⃣ Same ball for first and second shot

If the bowler uses the same ball for the strike shot and the spare attempt:

They must use all drilled gripping holes on both shots.

They cannot use the holes for the first ball and then ignore them on the spare with the same ball.

🔍 Special Case: Two-Handed Bowlers

Two-handers may have no thumb hole (modern rule), but:

If a ball has any drilled gripping holes, including a thumb hole, they must be used.

If a two-hander wants NOT to use the thumb, the ball must be drilled without a thumb hole (a balance hole is no longer legal).