When is a dead ball called, and what if someone bowls on the wrong lane?

On a dead ball, the delivery doesn't count, the correct pins are respotted, and the bowler rebowls. A dead ball is called when:

• right after the delivery, someone points out that a pin was missing from the setup
• a bowler bowls out of turn or on the wrong lane (see below)
• the bowler makes physical contact with another person or a moving object during the delivery (the bowler may choose to keep the pinfall instead)
• any pin is moved or knocked down while the ball is being delivered, before the ball reaches the pins
• the ball hits a foreign obstacle, such as a sweep bar that comes down early

Wrong lane: it's a dead ball and a rebowl on the correct lane if one bowler bowls on the wrong lane, or one bowler from each team does. If more than one bowler on the same team bowls on the wrong lane in turn, all deliveries stand, and everyone switches to the correct lanes from the next frame.

Not a dead ball: pins set slightly off spot but not missing. It's your job to check the rack and ask for a respot before you throw; once you deliver, the setup is accepted.