Blackwood

Theory of Distribution

A formula applied when missing four cards including the queen.

North - S - KJ1074

South - S - A862

South lays down the ace and both defenders play low. On the second round West plays low, and south has to decide whether to finesse or play for the drop.

Mathematically it is extremely close. Blackwood suggests a rule based on the theory of symmetry:

If the combined North-South holding in their shortest suit is

      1. five cards, or four cards divided two-two - play for the drop
      2. four cards divided three-one or four-zero,

or fewer than four cards - finesse

**This theory can only be applied when there are no indications from the bidding or the play.

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