Another Entry Problem
K J
9 5
A 10 8 7
Q J 10 8 7
10 2
Q 6
K Q J 6 4 2
9 3 2
9 8 6 5
J 8 4
9 3
A 6 5 4
A Q 7 4 3
A K 10 7 3 2
5
K
North/South cannot make
6 NT on a diamond lead, because they only have 8 top tricks.
A
6 ♥ contract is doomed if the defense takes its club ace and eventual heart trick.
6 ♠ does not make on a diamond lead because North can set up his clubs, but cannot draw trumps
and preserve an entry to run them.
The only slam to make here is
6 ♣.
If the defense leads a diamond, it seems like they still prevail. North solves the problem, however, by ruffing one diamond with the club king,
which strips East of his last diamond and unblocks the club suit.
Declarer crosses to North with a spade and leads top clubs until East takes his ace, leading to this:
Whatever East leads here, North has the spade king entry to draw the rest of the trumps and then run the major winners.