Rosenkranz Double & Redouble Convention

The Rosenkranz double and redouble convention is used to respond to partner's overcall when right-hand opponent has made a forcing response to his partner's opening bid (a bid in a new suit or a negative double)

Examples

1. Bidding W 1C N 1H E 1S S ?

South S9 2 HK J 10 D10 8 5 3 CA 9 8 4

Support double (6+ HCP  3+ H) 1 round Forcing bid showing a three-card trump support, with the ace, the king or the queen

2. Bidding W 1C N 1H E 1S S ?

South S9 2 HJ 10 6 DK 8 5 3 CA 9 8 4

2H (6-9 HCP  3+ H) limiting Non forcing bid showing a three-card trump support, without the ace, the king or the queen

3. Bidding W 1C N 1H E x S ?

South S9 2 HK J 10 D10 8 5 3 CA 9 8 4

Support redouble (6+ HCP  3+ H) 1 round Forcing bid showing a three-card trump support, with the ace, the king or the queen

One other thing to talk over with partner: Do you play Rosenkranz when RHO bids NT ?

Copyright 1999 BridgePassion.Com

Another use suggested by Mike Lawrence

Rosenkranz Doubles used when you are a passed hand and responding to partner's overcall.

All these factors must be in place. Your LHO opens, RHO bids a new suit and partner overcalls at the 1 or 2 level. LHO raises partner's suit or makes a Support Double. (If they use a Support Double you can use redouble to show an honor raise). You have a single raise with 3 card support with or without an honor.

Here are some examples:

1
W N E S
1C Pass 1H
1S 2H ?
2
W N E S
1C Pass 1S
2D 2S ?
3
W N E S
1H Pass 2C
2D 3C ?
4
W N E S
1H Pass 1S
2D Dbl* ?

*Support Double