Rosenkranz Double

Rosenkranz Double is an artificial raise of overcaller's suit to the 2 level, showing 3-card support for partner's suit, 6-10 points, and an Ace or King in that suit. By extension, a natural raise of the suit would deny an Ace or King in the suit.

If this player's RHO has doubled instead of bidding a new suit, this player can redouble in place of being able to double.

This is a defensive bid, intended to make it easier for the overcaller to know how to play the suit on defense.

For example, if the overcaller knows that partner has a top honor, he can underlead his own top honor to put partner on lead. Underleading with a low card tells partner to lead back the lower side suit, while underleading with a higher card asks for the return of the higher side suit.

This can be a huge advantage if overcaller has a roughable void or an AQ suit he wants led through declarer, etc.

If this player had 10+ points and support, he should cuebid rather than double or raising. With more than 3-card support, a Total Tricks raise should be made.

For more information, try bridgeburn.com.

Bobby Wolff says that Rosenkranz Double shows 2-card support - either Ax or Kx.