Rosenkranz Double

The Rosenkranz Double is used when your LHO (left-hand opponent) opens the bidding, partner makes an overcall, and RHO (right-hand opponent) also bids. A double is artificial, showing 3-card support for partner's suit with at least one of the top three honors. The purpose is to help partner on defense should the opponents win the auction.

K73 83 KQ93 T873

West      1 North     1 East      2 South     Dbl 1 (1) Rosenkranz double, showing 3-card spade support with a top spade honor.

In contrast, a simple raise of partner's suit denies a top honor in that suit. For example:

9873 AK5 JT9 965

West      1 North     1 East      2 South     2 1 (1) Rosenkranz, showing a 3-card diamond raise without a top diamond honor.

Rosenkranz doubles are used through the 2-level. The choice must exist to either (re)double or raise partner's suit to the 2-level.

Both the direct raise and the double show 6-10 points. A stronger hand with support must cuebid instead to show 10+ points.

73 A54 K7532 973

West      1 North     1 East      1 South     Dbl 1 (1) Rosenkranz double, showing 3-card heart support with a top heart honor.

QJ3 842 J53 A854

West      1 North     1 East      Dbl (1) South     Redbl 2 (1) Negative double (2) Rosenkranz redouble for spades. The convention is applicable as a redouble if RHO makes a double.

The Rosenkranz double is named for inventor George Rosenkranz, a preeminent Mexican expert.