Another deal from the Tollemache final in February, reported by Michael Newman who was kibitzing the event.
"Only eight out of sixteen tables managed to reach the laydown grand slam in clubs. John Holland and John Hassett were among the eight successful pairs in this regard.
I was watching Holland/Hassett bid this hand and John Holland took over 30 seconds before deciding to respond one diamond rather than one spade. If the South hand was a weak notrump then checkback would still allow a possible spade fit to come to light. I believe that this was the key bid in making it so much easier to reach the grand slam. Once South jumped to two hearts North knew that it was simply a question of small or grand slam. North was clearly too strong to sign off in three notrump after South continued with three diamonds and so simply bid four clubs. Now South bid RKCB and one keycard in the North hand was confirmed. Now South asked for specific kings or alternatively by bidding five notrump is saying 'do you fancy a grand slam?'. In these circumstances it is generally accepted that the asker must have at least one of the kings excluding the king of trumps. So North knew that South must have at least AKQ to six clubs and AK to four hearts plus the ace of diamonds. Therefore, barring exceptionally bad distribution, there must be thirteen tricks available in clubs.
The other Manchester pair failed to reach the grand slam partly because North chose to respond one spade at his first bid. The difference being that the jump shift of two hearts in the Holland/Hassett sequence showed at least nineteen points and was unconditionally forcing to game whereas after a response of one spade a reverse into two hearts only showed a good sixteen or more points."
Thanks to Michael Newman.