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Bridge odds – chance an honor drops

Brenner CH

Suppose you are missing Kx in a suit. It is (exactly) 52% that the suit splits 1-1. Everybody knows that.

How about missing Q432? J65432? etc.? Will the suit run if you play it from the top?

"Well-known" rule – chance of honor dropping

Missing 2k cards (0<k<7) including one card of particular interest, the probability that either the suit breaks evenly or that the particular card is in the short hand is close to (51+k)%.
253.13%Q fourth
354.01%J sixth
455.03%10 eighth
556%10 missing, Ace not long
657.04%12 missing, Ace not long