Rule of Nine – Rule of 9

The Rule of Nine is a concept employed by the responder after a certain bidding situation, which is described below. An example should clarify the situational element.

The question for North, the opener, is whether to reopen the bidding with a double. The situation is that North has opened the auction, the left hand opponent, East, has made an overcall, which is then followed by two passes.

There could be two reasons why South passed:

1. South has no values.

2. South has values and wanted to make a Penalty Double, but could not since a double would have been interpreted as meaning the two unbid suits.

In determining the correct reason as to why South passed, the inference made by North is that South has values if North is short in the suit of the opponent, two or less. In the case that North holds three or more cards in the suit of the opponent, then the inference is that South has no values, with which to bid.

Therefore, North should follow the guidelines below when deciding to reopen the auction with a double:

1. Reopen the bidding with a double if the number of cards held in the suit of the opponent is two or less. This guideline holds true even if the holding of North is not up to standard for a Takeout or Reopening Double.

2. Pass, completing the auction, in order to defend based on the inference that holding three cards or more in the suit of the opponent, partner has no values. This is the normal guideline. In the case that North has substantially more values to continue the auction independently, then North should take such action by bidding another unbid suit or employing a cuebid per partnership agreement and allowing partner to make a preference bid. A double, in this instance, should not be employed.

When North decides to reopen the auction with a double, then the partner should take some action. The Rule of Nine assists South in deciding to take the correct action.

However, the partner, after a reopening double, should:

1. Bid his/her best suit.

2. Raise the suit of the partner, in this case North, with a minimum of two or more but no less.

3. Pass for penalty when holding length and defensive values in the suit of the opponent.

The Rule of Nine can assist the partner, who has been forced to respond, in arriving at the best action.

The concept is explained below:

1. The partner, in this case South, adds:

a. the level of the contract plus
b. the number of cards held in the suit of the opponent and
c. the number of honors held in the suit of the opponent (this includes the 10)

2. If the calculated number is nine or more, then the partner, South, passes for penalty.

3. If the calculated number is eight or less, then the partner, South, should bid.

For example, if South, in the above example, held hearts AQ987, which is the suit of the opponent, then the calculation is:

Level = 2
Number of cards held in the suit of the opponent = 5
Number of honors held in the suit of the opponent = 2
Total = 9
Rule of Nine: South should Pass

Another example, if South, in the above example, held hearts AQ97, which is the suit of the opponent, then the calculation is:

Level = 2
Number of cards held in the suit of the opponent = 4
Number of honors held in the suit of the opponent = 2
Total = 8
Rule of Nine: South should take some competitive action.