- South doubles the 1♠ bid for 'takeout'.  In this case it is based on a strong hand with, primarily, a long (6+card) suit.

- North bids 2NT to show 11-12HCP and good Spade stops, this is usually played as Game Forcing (GF).

- South bids 3♥, opposite the GF bid this bid might only show 5+cards.

- North bids 3NT to show 0-2 cards in Hearts and suggests stops in the other suits.

- South bids 4♣ to show a second suit (and a dislike of NT).

- North bids 4♠ to show a first round control and a fit with the Club suit.  It also leaves space to explore slam.

- South bids 4NT 'Roman Key Card Blackwood'. In this case the key suit is Clubs; the last natural bid suit.

- North bids 5♥ to show 2 Key Cards (A♠ and K♣) without the Q♣.

West leads the 9♠ to dummies A♠.

Dummy plays 109♥ and East follows with West showing out on the 2nd round.

- You have 11 top tricks and a 12th could come from either a 3-2 Club break or 10♣ finesse when East has a 4-card Club suit.

Problem

If East does have a 4-Card club suit then he has chosen to open on 5314 shape with 9-10 points (assuming a singleton Diamond honour).  Meanwhile, West would have an 8-card Diamond suit to an honour and has not bid.  Think again!

It is more likely that East has KQ♠, AK♦ and a 5+card Spade suit, and West has a 3 or more card Club suit.

Do you play on Clubs, or is there some other way?