2-on-1 Eight Ball is a variation on the standard 8 ball rules for three players.  Two people are on one team and the other player is alone.  This variant is also useful if the single player is better than the team or two players.  It gives an advantage to the two-person-team.

There is also an option for play when there is a missing object ball, this is useful for occasions where a ball is completely missing, damaged or if the ball was not released by the for-pay table mechanism.

Equipment:

• 15 pool balls numbered 1-15
• Two cue balls
• Triangle rack
• Pool table

The basic play is the same as Eight Ball including using a single cue ball.  The two-person-team takes turns taking shots.  This is different than some team based play where alternating turns are traded.  If player A from the two-person-team sinks a ball, then player B from the two-person-team gets his/her the next shot.

Once the two-person-team sinks a ball the additional cue ball is placed on the table on the head spot.  From then on, either cue ball may be used by any player.  The cue ball hit by the player is the active cue for that shot.  The other cue ball is just a dummy ball.  It may be hit first without a foul, it may be sunk without a foul.  If it is sunk, it is placed on the head spot without penalty and the current player continues their turn, even if no other object ball is sunk.  As per normal rules, if the active cue is sunk it is a scratch and the other player/team gets ball in hand.  See 7.0 of the official billiard rules.

If the single-player gets 2 balls ahead of the two-person-team the handicap is activated.  In this play both players on the two-person-team take a shot at the same time.  Each player chooses a cue ball and they count down and take their shot simultaneously.  This requires coordination to avoid unintended consequences.  Both cue balls are active so if one is sunk it is a scratch.  If both are sunk one is placed on the head spot and the other is ball-in-hand to the other player.

If either or both players sink their object ball the two-person-team continues their turn.  Only one object ball needs to be sunk to continue their turn.  When there is a single object ball other than the 8 ball left the two-person-team no longer takes simultaneous shots.

Both of the simultaneous shots must be legal shots.  Particularly, the cue must first hit an object ball from his/her group and the cue or object ball must hit a rail or the object ball must be pocketed.  See 7.3 and 7.4 of the official billiard rules.

The simultaneous shot rule stays in effect for the remainder of the game, even if the single player is no longer ahead by 2 balls.

Special rule for missing object ball:  If an object ball is missing the additional cue ball is racked with the other balls.  For the break this ball is a stand-in for the missing ball.  After the break, either cue may be used as the active cue, the other one is a stand-in for the missing ball.  This gives a slight advantage to the team that has the additional cue-ball-stand-in.  For this reason, the two-person-team can optionally pre-select that group of balls prior to breaking.

This special rule may optionally be used even if there are no missing object balls.  In this case, one of the object balls is swapped for the extra cue in the rack.