Rules of the game
A flip of a coin decides who starts. The game starts with the red ball on it's spot. The player to start takes a white ball from the trough at the front of the table and places it in the D for the first strike. The game is normally played by 2 people but can also be played by 3 or 4 players.
Each turn consists of a number of strikes and comes to an end when a player makes a non-scoring strike or a foul stroke.
A strike is taken by the player taking a white or red ball from a trough at the front of the table, putting it within the D at the front of the table and then hitting it with the cue. Normally, players will pick the red ball if it's available because this gives double points. The aim is to strike another ball on the table in such a way that at least one ball ends up rolling into a hole. If this is achieved, the player continues his break with the next ball.
Any white ball that falls into a hole scores the number of points indicated by that hole. If the red ball falls into a hole, it scores double the points indicated by that hole.
A foul is committed by:
knocking over a skittle
causing a ball to return back behind the baulk line
failing to hit any other ball with the cue ball
causing a ball to leave the table.
In all of these cases, the player's turn finishes and any points scored in that turn are lost. Additionally, if the black skittle has been knocked over, the player's entire score for the game is reset to zero.
At the end of a players turn, any balls on the table surface remain where they are and the next player begins his turn by retrieving a ball from the trough, placing it in the D and striking it up the table.
Less oft-used Rules
If there are no balls available from the trough with which to take a strike, the ball nearest to the baulk line is retrieved instead.
If a skittle is knocked over and a ball prevents it being replaced, the ball should be returned to baulk.
If a ball comes to rest in the D, it should be returned to baulk.
If a skittle is moved but not knocked over, the skittle should be returned to it's spot before the next strike.
Where a strike causes both a white and a black skittle to be knocked down, if the black skittle was toppled first, the black skittle penalty is taken (entire score is reset to zero); if the white skittle was toppled first, the white skittle penalty is taken (that turn scores nothing).
Normally, the games are coin-operated and each coin gives a game of a certain length of time between 15.5 and 19 minutes. After that time, the baffle-bar drops inside the table which prevents potted balls from returning to the trough at the front of the table. Once that happens, play continues as described above but the number of balls in play gradually decreases. Sometimes, the last 2 or 3 balls are all potted in one strike in which case the game ends at that point but, more usually, the time comes when there is only one ball left.
The Final Ball
If it happens that only one ball remains, a special rule comes into force. Before it is struck, the two white skittles are placed into the 50 holes and the top holes are guarded to prevent the ball being lost into any of those holes. Then, the game can only be ended by a player hitting the ball from the D in such a way that it bounces off the side cushion and falls into the the 100 hole or 200 hole. Needless to say, the risk of knocking over the black skittle while attempting to achieve this feat is significant. Players take turns to do this until either the ball is successfully potted in the 100 hole or 200 hole or else the game is forfeited because the ball falls into a different hole or the black skittle is knocked over.
If the final ball strikes one of the white skittles, this is a foul and if the ball should then enter the 100 or 200 holes, the game is forfeited.
Of course, in the case where the difference in points is greater than 200, there isn't much point in continuing because the leading player can avoid going anywhere near the skittles and be guaranteed the win. Technically, the game isn't finished until the last ball is sunk but it is normal in this case for the losing player to offer his hand and concede the game.
Alternative rules and table variations abound. The time of the game can be set from anywhere between 5 minutes and 20 minutes, the number of balls and skittles can vary. Values of holes can differ as can precisely where the skittles are located. Some rules state that the red ball is always placed back onto it's spot each time it is potted. Others have a spot for the first white ball too. Some rules say that the last ball can only be potted in the 200 hole.