All experienced players are familiar with the suit-preference signal. Commonly this occurs when giving partner a ruff, or when a continuation of the suit led is pointless (such as with a singleton in dummy at a suit contract), or to indicate your side entry in notrump, or to show which suit you have strength in and various other scenarios, such that a complete list would be tedious.
Most suit-preference situations could be described as active, because you want partner to lead something, usually right away. For example, if you give partner a ruff, you want him to return the indicated suit; or if the continuation of a suit is pointless, you want an immediate shift. Even in cases where you show a side entry in notrump, the message to partner is that he can lead that suit to reach you if he gets in.
Another branch of suit preference could be described as passive, because the goal is not to have partner lead something but to discard correctly. To illustrate, consider the following layout, which is based on a recent online deal:
On Wests diamond lead, East plays the nine, and South wins the king. Declarer runs the club suit, West playing the four (count) then the nine, suit preference to indicate his side entry is in spades as opposed to hearts.*
*Those who use the Smith echo may treat this situation differently. I deliberately do not play Smith, because my defense is count-oriented (followed by suit preference) and the two methods do not mesh.
On the fourth club, East has an awkward discard, but guided by Wests suit preference he lets go a spade. Alas, declarer is now able to establish his spade suit to make the contract with an overtrick, no less. What went wrong?
The answer is that West was applying active suit preference in a passive situation. The concern here is not what East should lead, but what he should discard on the last club. Holding three hearts (with three in dummy) West knows that East can safely pitch a heart from four, so he should show suit preference for hearts. East then knows he must keep spades, and the contract is defeated.
Below is another example from a deal that occurred last year. In this case only an overtrick was at stake, but imagine the cruciality if a grand slam were bid.
With 12 top tricks, declarer grabs the A and proceeds to run diamonds. How should West signal? My method is to play the 7 first as count, then 6-3 would be suit preference for hearts, and 3-6 would be suit preference for clubs. So which should West show?
Holding J-9-4 versus 5-4-3 it might seem logical to show preference for hearts, but that is active thinking in a passive situation. East needs to know what to discard, not what to lead. With six clubs in view, West knows that East can safely part with a club from four, so he should show suit preference for clubs, playing 7-3-6. This warns East to keep hearts, holding declarer to 12 tricks.
In order to distinguish cases for active versus passive suit preference, ask yourself whether partner will have to lead or discard first. If the answer is to discard, your suit-preference goal is to help him get it right.
© 2019 Richard Pavlicek