Defence is arguably the most difficult part of the game. Spectacular when you get it right, ugly when you screw up.
South opened 1♠, and North responded 1NT (some would have raised to 2♠ but that's beside the point). Now 2♥ from opener and 2♠ by North, raised to 4♠. End of auction.
You lead ♦A and continue with the king, ruffed by declarer. He cashes ♠K and leads a small to dummy's ace, your partner following small and jack, and you discard a club. Next he advances ♥J, losing to your queen.
You go into the tank, or do you? At least declarer doesn't claim. What now?
Roland

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S: 4S
Lead: DA