This convention provides insight into the distribution of high cards held by the defenders when the opening lead is the fourth highest card from a long suit. It is calculated by subtracting the rank of the opening lead from the number eleven. The resulting number indicates the total number of cards higher than the led card held in the combined hands of the leader’s partner and dummy. For example, if the opening lead is a four, eleven minus four equals seven, indicating seven cards higher than the four are held between the leader’s partner and the dummy. This allows inferences about the location of specific high cards.
Understanding the numerical tool’s implication is crucial for both declarer play and defensive strategy. For declarer, this knowledge aids in determining the likelihood of a successful finesse or the optimal line of play. For the opening leader’s partner, it helps in signaling effectively and making informed decisions about whether to play high or low cards. Its application, dating back many decades, has become a fundamental element of standard bridge play, enhancing communication and strategic depth between partners at the table.