In bridge there are many coups, some of which are named after the person who first dreamed them up. Well, because the following three situations all involve one defender holding Kx, I am claiming title rights to this particular coup by simply linking them together.
Given the actual layout in each scenario, the defender with Kx should always take a trick with the king but fails to do so because of erroneous thinking .
1. Here declarer has a 5-5 trump fit missing the AKx of trumps, but with Kx sitting to his left. When he volunteers the queen of trumps towards dummy's J10 to five, the hapless defender hops up with the king only to see it fall under his partner's stiff Ace. Many commenters argue the play of the king is foolish, because if declarer holds the Ace, he had a legitimate line where he can escape even a single trump loser.......either by playing the Ace hoping to find the stiff king, or by taking a simple finesse through his RHO. Indeed, this particular scenario has been well documented in many bridge books, often quoted as an example of The Idiot's Coup.
2. Again declarer has a 5-5 trump fit, but only missing Kxx. Again the Kx is to his left, well place over declarer's AQxxx. However, when he volunteers the queen of trumps towards dummy's J10 to five, the hapless defender decides not to hop up with the king desperate to avoid it being smothered by partner's stiff Ace. However, when the queen holds, declarer then produces the Ace from his hand taking out the king in the process..........another example of the The Idiot's Coup. Many commentors argue ducking with Kx is foolish, because if declarer suspects, say on the bidding, that the king is off-side but guarded......... this ploy is the only legitimate line he's got to hoodwink the defence from taking a trump trick.
3. Yet again declarer has a 5-5 trump fit missing the AKx of trumps, but with Kx to his right. The ploy this time is to persuade the defender with Kx to ruff small when desperate to stop the run of winners from a powerful side suit played out from dummy. By ruffing in prematurely, the hapless defender is shocked to see declarer over-ruff.....which enables him to then produce a small trump to crash the RHO's king under his partner's stiff Ace. Many commentors argue that ruffing small is like sending a small boy to do a big man's job. His partner may have the stiff queen, which means the defence would fail to make a single trump trick. By rising with the king, it guarantees two trump tricks if partner does have the stiff Ace, and certainly one trump trick if partner holds the stiff queen ( classic uppercut stuff ). Indeed, this last scenario has also been well documented in many bridge books, under the title of The Galileo Coup.
So by recognising that these three situations all involved error-prone defenders failing to take a trick holding Kx of trumps in circumstances where idiots might have succeeded, I Bigot-Johnson am the first to bring them all under the same one umbella......which of course entitles me to collectively define them as The Bigot-Johnson Coup.