NORTH  KT3  T72  Q63  A864  Q9  Q53  A975  K752    542  64  JT84  QJT9    AJ876  AKJ98  K2  3

Dealer: West    Vul: Both   MP Scoring West Pass Pass Pass Pass Pass Pass North Pass 21 4 5 6 East Pass Pass Pass Pass Pass South 1 32 43 6 Pass

South's Auction:
Perhaps South forgot that 'the convention' was tonight played in 4th seat as well as 3rd.
To tonight's sleepy South, 2 showed a 'standard' 10 or 11 points, 5+ diamonds, denied 3 spades and was not forcing.
South's jump to 3 was game forcing (15+) with 4+ hearts.
When North alerted 3, it might have begun to occur to South that 'the convention' had been missed, for a standard 3 bid is not alertable.
When North bid an unexpected 4, even if South had been deaf and not heard the previous alert, the 2 bid's meaning should have begun to suggest itself, unless North had had such as 4 hearts, 11 HCPs and perhaps some short suit in addition to already 5+ diamonds that might have revalued to as much as 15 points for a passed hand! South's ambition grew!
With 16 HCPs and 3 for shortness, all that was required from North for the slam total of 33 points was 14, and opposite a potential North holding x xxxx AQxxx Axx, there might just be a grand slam.

North's Auction:
To North, South's initial 3 bid might have been just a game try with short hearts.
Was North's hand good enought to accept that invitation? With one of the top two trump honours, an outside ace and a hand already advertised as less than a limit raise, North had close to the best hand possible. If the Q had been the K, North with two kings and an ace would probably have given a limit raise. How about with two aces and a queen? Still a limit raise? Still not one?
North decided to accept South's game invitation and instead of bidding 4 directly, cuebid the A, just in case South had a powerhouse.
South 4 heart void advert, was to North a red cape to a bull. North had nothing wasted in hearts. It was now a 30 point deck and all 9 points were working.
Perhaps there was a grand slam on this hand to be had! Such slams are relatively rare. A confident North might have leapt to 6 to deny the K.
A thoughtful North might instead of even that have asked for Keycards 'knowing' that the A couldn't be part of a Keycard response, and that if South had held 7+ spades without the ace, it would have been reported as held, based on it's tendency to drop on the first two round of trump drawn.
If North HAD asked, South would have replied 5 showing two keycards without the Q and South could have nixed the slam, off a keycard and the queen of trumps when partner could have 'lied' about it.
Blame-shifting is sometimes handy, sometimes not.
In bidding 4, perhaps South was expecting such as the Q instead of the Q. With a heart void, however, certain the Q would be important, wouldn't it?
Wouldn't long clubs have been advertised with 3, rather than the 3 shortness showing?
North decided that a)4 would have been too pessimistic; b)4N would have been dicey and contrary perhaps some rule about asking for keycards with a void (even if partner held it) and c) that the frequency of slam for a 1 opener, opposite a 3 trump constructive raise, was so rare that South should be given one more chance to quit and admit that it had to be still another 8 months before the partner was due for one, no matter how good bidding technique was, by bidding a now tentative 5.

Back to South's Auction

What was 5? Was it a strong invitation to 6 that couldn't cuebid again? It couldn't show spades, for spades were earlier denied.
It went past 5 and hearts were agreed, so it had to show a spade control and be a heart grand slam try!
Could it really be the jackpot x Qxxx Axxsx Axx ?
Surely it was South's turn to cuebid the important 6.

Back to North's Auction

Spades were agreed as trump, South's supposed to simply bid slam if it's there.
The 6 bid is a grand slam try? Already simple opener opposite constructive raise is 'pushing the envelope' on a plausible slam and partner's suggseting a grand slam?
"Director! I'll take 30% on this board if they'll give it to me. Can I offer it up?" occurred to North.
Would you as North have bid the grand slam playing such a system?

Back AGAIN to South's Auction

What's 6? Aren't hearts trump? Don't you just bid 7 if you can make it? Is 6 a choice to pick between 6N and 7? Is it a try for 8? 9? Do I show 2nd round control of clubs en route with 7?
B.S.    Pass

The small slam wasn't all that bad a proposition, considering the bidding derailment and requiring little more than two finesses (about 25%).
Looks like North's thought of a 30% deal was a bit optomistic.
In actuality, North South scored 9% on the deal (1 matchpoint out of a possible 11 for -100 vulnerable).