Another explanation is that the phrase comes from the game of Kelly Pool, in which players are assigned one of 16 balls to pot, with the ones with the lower numbered balls playing first. Players who are dealt balls with values greater than eight are unlikely to win the game.
In modern parlance, an 8-ball is a term used to describe a very low-quality ball, usually made from plastic or rubber. The name comes from the fact that these balls average about 8 per box.
The word "8-ball" has become synonymous with "guaranteed victory", since most balls in a pack of 8 are duplicates: 7 will end up in the pocket and 1 on the floor. Thus, if players receive equal numbers of boxes then they can be certain to win more times than not.
This idea originates with the game of pool, where getting 8 balls in each corner pocket = win. In other words, every time you shoot a ball at a object (such as a peg) that isn't blocked by another object (such as a wall), there's a 100% chance that it will go in the pocket. Since we know that there are 20 objects in total, this means that you will win 100% of shots that don't hit anything.
We can also estimate the probability that a player will win using simple math.
As recounted by Harold Hadley in Behind The Eight Ball, a short story published in the Daily News, the expression "behind the eight ball" refers to a position in a game of pool in which a player cannot make a direct shot at the target ball because the black eight ball obstructs the cue ball (New York City, N.Y.) or the red seven ball (everywhere else). The eight ball is black because that was the only color available when the expression was coined in the 1930s.
The term came into use among players of the game during this time and has remained popular ever since. It comes from the fact that before each shot, the balls must be counted to make sure that no one has been scuffed by a spectator or knocked off its table. If so, play continues with the next ball. But if all the balls are on the table, then it's time for someone to make a shot.
This anecdote is interesting because it shows that not everything in life follows a logical pattern. The eight ball is always black because that's what was available at the time. However, if we looked around today, we would probably see some colored balls as well.
Also, it's important to note that although the eight ball is usually black, this isn't always the case. There have been occasions where other colors have been used instead (red seven, blue six, etc.).
In a dangerous circumstance A player whose cue ball (the ball that strikes the other balls) is behind the 8 ball is unlikely to make any shots in certain pool or billiards games. If this occurs, the person who shot the ball can either shoot again or call a foul. If he shoots again and fails, then there is no limit to how many times he can be defeated by the same shot.
The term comes from pool, where eight balls are used, with one ball called the cue ball. When the cue ball is struck, all the other balls are hit. So if the 8 ball is struck but not put into play, that means that no game can be won or lost with that shot. However, if some other ball is sunk using information obtained from the 8 ball strike, then that ball would become the cue ball for future shots.
For example, if ball #8 is struck but not sunk, that means that no score can be made with that shot. However, if we get information from that shot that tells us which way ball #1 is going, then we could line up to shoot it perfectly to match that direction. Or if we wanted to confuse things, we could try to sink both balls on the next shot!
This situation arises very often in practice games.
The remaining balls can be placed in any order. Ten-ball is a contemporary pool game. It is a rotating game similar to nine-ball, but more difficult, because it uses ten balls instead of nine, and the tenth ball serves as the "money ball" instead of the nine. The object is similarly to score as many points as possible before your opponent does.
There are several different types of shots in ten-ball. They include: