What is a free ball in snooker?

TL;DR

In snooker, a free ball is awarded after a foul when a player is snookered and cannot make a legal shot. The referee allows the player to nominate any other ball on the table to play instead.

Key points

A free ball is awarded after a foul in snooker.
It occurs when a player is snookered and cannot play a legal shot.
The referee allows the player to nominate another ball to play.

[BBC]

In snooker, a free ball can be awarded after a foul has been committed in which the player about to play their next shot is left snookered and cannot play a legal shot onto the intended ball.

When this situation occurs, the referee may declare a free ball, which allows the player to nominate any other ball on the table to play in substitute of the one they were due to play.

In order for a free ball to be awarded:

A foul must have been committed
The incoming player does not have a clear shot on both sides of the colour of ball that is due to be hit
The referee determines that the ball is in a snookered position as the direct result of a foul

If the nominated replacement ball is potted, the number of points awarded for potting the replacement ball is the same as it would have been for the initial ball.

For example, if a player is aiming to pot a red ball but instead pots the replacement ball which is black, the shot would still only be worth one point.

How a 'free ball' led to O'Sullivan's record 153

A snooker referee placing balls on a table

A 'free ball' is traditionally awarded when a player is unable to hit a red due to being snookered by an opponent's foul [Getty Images]

In a typical frame of snooker a player pots a red, then a colour and so on until all the reds have been cleared.

This changes slightly in the instance of a free ball. In most cases, a free ball comes in a situation where a player is meant to be aiming to hit a red.

When they pot a free ball, they move on to a colour and should they pot that, they will move back on to red where a normal sequence would start from.

Because a red is not removed in the instance that a substitute ball is potted, it can create a unique situation where a player can actually be given extra points on top of their break.

An example of this came last month when Ronnie O'Sullivan set a world record break of 153, despite the maximum points in a break officially being 147.

This occurred when O'Sullivan was awarded a free ball and potted a green, followed by a black. That gave him eight points before he continued his break in a traditional way.

O'Sullivan followed that up with 15 reds, 13 blacks, two pinks and then all of the colours.

The break in a traditional fashion was worth 145, but with the eight points coming from the free ball, O'Sullivan's actual break finished as a 153.

This article is the latest from BBC Sport's Ask Me Anything team.