A dificult hand at the start.

East will pass.

South has a choice, 1♦  or a bit off shape and probably a bit too strong (14HCPs and a 5 card suit,  with the Kaplan hand evaluator gives 16.1) 1NT. So probably 1♦ is best with the aim to rebid NT to show 15-16 HCPs.

West can either do a weak  3♣  (that probably denies a 4 card ♠ suit) or 2♣ that is more likely to allow the ♠ s to be shown, but also gives the risk that opps have a ♥ fit.

 Over 2♣ North will have a choice of bidding a weakish 3♦ bid or an unassuming cue bid UCB (Andrew Robson on UCB) to show the good support for ♦ s. A bit weak for a double and with a ♦ fit, less likely to find a major fit.

Over a 3♦ East could double to try and find a major fit (also less likely to find one as already have a ♣ fit). If he soes that South finds 4♠ which can make with the double fit and favourable ♠ fit. Over the double South may bid 4♦ and West will bid 4♠ . With the adverse vulnerability bidding 5♦ is risky and minus 2 doubled is -500.

In 4♠ from West North has the choice of leading a ♣ singleton or partners ♦ s. Either could be right, the singleton ♣ lead puts pressure on declarer but it still makes after the obvious ♠ finesse.

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