This concept was devised by Mr. Malcolm MacDonald. The article was published in The Bridge Bulletin, January and February 1998. It is employed to determine whether the action of a squeeze play ought to / should be considered when the possibility of winning an additional trick presents itself during play.
Such an action should also be considered even when there is another, second possibility available such as a finesse. The rule or guideline offered for determining whether a squeeze is possible or even preferable is summarized by the author as below:
| 1. |
Count the number of tricks that must be lost. |
| 2. |
Count the number of winners that can be run. |
| 3. |
And count the number of cards that must be held in the threat suits by one defender. |
| If the total is 14, then a squeeze may be possible. |
| If the total is 13, then a squeeze is not possible. |
This Rule of Fourteen can be applied at trick one or whenever the declarer has made the determination that the contract can be made minus one trick, or within one trick of making the contract. This Rule of Fourteen may also be employed against each defender separately for double squeezes.
Tricks that can be won in the threat suits may be counted with winners or with cards that must be held by a defender in the threat suit, as long as they are not counted twice. It is the opinion of the author that Pseudo-Squeezes always add up to 13.
In the words of the author the Rule of 14 does not assist the declarer to determine whether the conditions necessary for the squeeze to succeed exist, nor does the Rule of 14 indicate the proper technique for the execution of the squeeze. The Rule of 14 simply indicates that a squeeze is possible. The Rule of 14 is effective because the central and basic concept underlying the squeeze play is that a defender does not have sufficient physical space in his/her hand to hold all of the cards needed to successfully defend, which, if the opposite were true, then the defender would hold more that 13 cards.
An example, as presented in the article, illustrates and clarifies this concept:
West leads the 
Ace and wins the second trick with King and the third trick with Queen. West then leads the 
Jack. South, at this point, can count nine tricks: 5 Spades plus 1 Heart plus 3 Clubs and is short one trick to fulfill the contract.
Since West doubled for Takeout, South will definitely lose the Heart finesse. South could also hope that the Clubs split 3-3 to set up the 13th Club as the trick necessary to fulfill the contract, but again this seems doubtful owing to the double by West, who has announced shortage in Spades, played 3 Diamonds, and promised 4 Hearts, leaving at least a 4-card Club suit.
Since all the qualifications and conditions for the application of the Rule of 14 exist, South begins to count as follows.
| 1. |
South has three tricks that must be lost, or have been lost. |
| 2. |
South has six winners that can be won. 5 Spades and 1 Club trick that has already been won. |
| 3. |
West, the defender, must retain two Hearts, namely  Kx and three Clubs, namely 1098 in order to defeat the contract. |
Therefore, applying the Rule of 14: 3 tricks that must be lost or already lost tricks, plus 6 winners or tricks that can be won, plus 2 which is the number of cards that must be held in the threat suit (Hearts) by one defender, plus 3 which is the number of cards that must be held in the threat suit (Clubs) by one defender equal 14.
After winning the 3 Diamond tricks and switching to the Jack, which Declarer wins, South pulls three rounds of trump ending in hand. West has to discard either a Heart or a Club.
West discards 2 to guard the possible Club winner. When the declarer continues to play two more trump tricks, West must find two more discards.
West is squeezed. If West discards a Club, then the 7 in the dummy becomes a winning trick and the declarer throws the losing Heart trick. If West discards two Heart tricks, then the declarer can play the Ace, dropping the King held by West, making the Queen the tenth trick, thereby fulfilling the contract.
Principle Works Both Ways
The principle of the Rule of 14 is generally applied to determine whether the introduction of a squeeze play is possible by the declarer. The same principle can also be employed by a defender to determine whether measures will be required to avoid a squeeze play by the declarer. The following illustration as presented by the author should clarify this possibility:
South |
|
West |
|
North |
|
East |
| 4 |
|
Pass |
|
Pass |
|
Pass |
West, on lead, plays the two top Diamonds, Ace and King, and continues with 4 after getting a count from partner, thereby knowing that the declarer holds only two Diamonds. Playing a third Diamond would set up the Jack in the dummy as a winning trick.
Declarer wins with the Ace in dummy and leads a trump. West may duck or not duck the first trump trick, but once West wins the Ace, the normal play would be for West to continue the Clubs, guarding the Spades. However this line of play will force the declarer to squeeze West in Spades and in Diamonds.
On such a play, West will recognize after the first or second trick that South has three certain losers: 2 Diamond losers and 1 Heart loser. The normal thought process is that West may assume that South has 8 Hearts based on the preemptive bid, 2 Diamonds, 1 Club, and therefore only 2 Spades.
Therefore, West must base his line of play on the off-chance that South has only 7 Hearts, 2 Diamonds, 1 Club, and three Spades, one of which will be a losing trick. Applying this strategy West sees a chance to defeat the contract.
Applying the Rule of 14, West counts:
| 1. |
South has 3 losers. |
| 2. |
South has 7 winners, 6 Hearts and the Ace of Clubs. |
| 3. |
West must retain 4 cards, the Queen and  QJ3. |
| The total equals 14. |
West must, therefore, continue Diamonds on the third trick although West knows that the declarer only has two Diamonds, and that an Avoidance Play must be initiated before the squeeze play can be activated by the declarer.
After South wins the third Diamond in hand by trumping, South forces out the Ace, and West is again on lead. West must continue the Diamonds ( 2) and East must trump, canceling the established Jack as a winner. As a result of this line of defense, this Avoidance Play, the declarer can no longer establish a squeeze play against a threat suit held by a defender and West, as a defender, has avoided the squeeze play by employing the Rule of 14.
If you wish to include this feature, or any other feature, of the game of bridge in your partnership agreement, then please make certain that the concept is understood by both partners. Be aware whether or not the feature is alertable or not and whether an announcement should or must be made. Check with the governing body and/or the bridge district and/or the bridge unit prior to the game to establish the guidelines applied. Please include the particular feature on your convention card in order that your opponents are also aware of this feature during the bidding process, since this information must be made known to them according to the Laws of Duplicate Contract Bridge. We do not always include the procedure regarding Alerts and/or Announcements, since these regulations are changed and revised during time by the governing body. It is our intention only to present the information as concisely and as accurately as possible.