Does East open a week 2♥ with his terrible 5HCPs? The vulnerability is favourable.NV vs. V.

If East opens 2♥ what does South do? Double as he doesn't have a ♠ stopper for a 3NT bid.

West should probably pass.

North will bid, 8 HCPs but with the K singleton in opposition suit it is probably worthless. A useful system over a weak 2 doubled is Lebensol. Which is 2N tells partner you have 0-7HCPs and tells him to bid 3♣ which will be passed (in this case) or converted.

In this case as South has a game forcing hand he will ignore 3♣ which may be passed. His choice is between a risky / gamble 3NT or bidding 4♣. 3NT will be passed. 4♣ will be raised to 5♣ by North and South will probably risk a 6♣ as 5♣ is likely to lose to 3NT if NTs makes -  a typical duplicate decision.

If East does not open with a weak 2♥ makes life easier for South. He will open probably  1♣ to show his shape and values with a rebid of ♥ s. Not quite strong enough for an Acol 2♣.

West will bid a preemptive 3♠ .

North will bid 4♣.

South then has a difficult decision 5 or 6♣ ? K♠ wothless, but a good idea of distribution and values, so well done to those that got to 6♣ .