paulhuggin

Until designations such as "small", "top" etc which do not designate the card to be played by rank are explicitly forbidden by the laws then declarer can use them freely. And if this is deemed to be coffee housing then how about running a long suit hoping for oppo to discard the wrong thing - is that not also trying to induce an error? And if the answer to my example is "oppo can work it out" then surely the same applies to working out whether a spot card is a winner or not?

I don't see how this is coffee housing any more than stronger opponents making better use of a bidding system than weaker ones. Declarer is not obliged to tell the defence whether the spot cards they are calling from dummy are winners or not (and it would surely open up a worse can of worms if they got that wrong, deliberately or otherwise). And how is declarer supposed to designate the 6 with J6 remaining - should they always name the card's ranking? that can get irritating at other times, which is why it's not part of the laws. It's not declarer's job to make sure defenders have been following the spot cards.