In
contract bridge
Contract bridge, or simply bridge, is a trick-taking game, trick-taking card game using a standard 52-card deck. In its basic format, it is played by four players in two Team game, competing partnerships, with partners sitting opposite each othe ...
, the Rule of 10-12 is applied when the
opening lead
The opening lead is the first card played in the playing phase of a contract bridge deal. The defender sitting to the left (LHO) of the declarer is the one who makes the opening lead. Since it is the only card played while dummy's cards are still c ...
is the third or the fifth best from the defender's suit. By subtracting the rank of the card led from 10 or 12 respectively, a defender can determine how many cards are higher than the card partner has led. Ten is used if the lead is fifth best and 12 is used if the lead is the third best.
Rule of 12 at the BridgeGuys website
/ref> The Rule of 11
In contract bridge, the Rule of 11 is applied when the opening lead is the fourth best from the defender's suit. By subtracting the rank of the card led from 11, the partner of the opening leader can determine how many cards higher than the card l ...
applies when the lead is the 4th best.
When following the Rule of 10-12, the lead is the third card from a three or four-card suit and the fifth card from a five-card or longer suit. Leading the third best is also applied to interior sequences (K J 10 x x) which is less ambiguous than the top of interior sequence. The third best lead from an interior sequence is called a coded 9 & 10 lead.
Sometimes opening leader may choose to lead the fourth best card from a four-card suit against a notrump contract if the third card is a spot card. The spot-card lead may give declarer a trick that he can't get if the fourth best is led. If the opening lead is the 7, the suit will be blocked and defense is unable to set up the 3rd winner in the suit.
Variation
Possible variation that helps giving count from 5+ cards suit is leading the third best from even number of cards and the lowest from odd number.
See also
* Rule of 11
In contract bridge, the Rule of 11 is applied when the opening lead is the fourth best from the defender's suit. By subtracting the rank of the card led from 11, the partner of the opening leader can determine how many cards higher than the card l ...
* Journalist Leads
Journalist leads are an opening lead convention in the game of contract bridge. The method is designed to solve some problems with traditional agreements regarding opening leads. It bears some resemblance to Rusinow leads but differences exist. Jou ...
References
{{DEFAULTSORT:Rule Of 10-12
Contract bridge leads