A bidding problem from the Corwen Trophy.
Vul vs non vul. matchpoints Dealer North
After your partner opens two clubs (game forcing or 23-24 balanced) your right hand opponent decides to make the auction difficult by jumping to three spades. You pass (double would be take out) and partner makes a take out double. What do you bid?
Your choices are between pass and four notrump to ask partner to choose a minor.
At any other vulnerability passing looks correct, but at this vulnerability you may not get a sufficient penalty to compensate for making five of a minor (if it makes).
On the deal in question four notrump would be the winning action. Three spades goes three off for 500, but five clubs makes for 600, see the full deal below.