This hand is in one of the bridge books i own.

The question is "What are the odds of making 7NT on a club lead, good enough to want to play there?"
A quick glance would suggest that this requires a 33 diamond break. About a 1/3 shot if i remember correctly. A slighty deeper glance will show a hidious number of squeeze posibilities.

-A simple squeeze can exist when either opponent holds 2 out of the following 3 KQ of hearts, 4 diamonds, 5 spades
-A double squeeze can exist when the hearts honours are evenly split south has 4d
-Im fairly sure I worked out that a guard squeeze could exist but sadly ive forgotten it

I also have two final points.
1; Would you want to be in 7NT by West in real life, where that mean North can lead a heart
2; Assuming a club lead what is the correct line of play to combine all chances?

How do you squeeze North when he holds the Heart KQ and 4 diamonds or just 4 diamonds and 5 spades?

When South has 4 diamonds there is always a squeeze (simple or double).

So when North has 4 diamonds, you can only make this when South has both KQ Hearts and 5 Spades.

So you can make it when South has 3 or more diamonds, or when South holds KQ Hearts and 5 Spades.

This is 0.5 + 0.5(3-3 Break (Half included already)) + (South holding JT doubleton diamonds) + (1 - those odds)(odds of either hand holding both H KQ and 5+ Spades).

If I'm right, I think this is good enough to be in (Over 2/3 chance, I think).

MY LINE

Win Club, KD (assume everyone follows), QD (no JT Diamonds),
then the AD, KS, AS and run all but 1 club, pitching a heart and a spade (while counting spades and watching for a diamond or Heart honour).

When South has last diamond, he cannot relinquish it and so you pitch the diamond as he must pitch a heart/spade in front of you). The pressure then turns to North who is protecting both Spades and Hearts and must surrender in 1, unless South had KQ H or 5+ spades, in which case he had to pitch the key control card.

When North has the last diamond, you must play as if South holds both the spade and heart guards and so pitch what he has left unprotected.

I think North can only be squeezed when he has all 3 guards (meaning a max of 2 clubs) and is squeezed on the 2nd last club and must pitch a heart honour or the last diamond/spade.

Is this right?