(569) Rosenkrantz Redoubles

This Week in Bridge

(569) Rosenkrantz Redoubles

© AiB                                                      Robert S. Todd
Level:  9 of 10                                        robert@advinbridge.com

General

When Left Hand Opponent (LHO) opens the bidding, partner makes an overcall, and Right Hand Opponent (RHO) makes a negative double, then Advancer is in the middle of a complex competitive auction.  Traditionally, a redouble in a competitive auction shows a strong hand (10+ points), but with everyone bidding it is not likely that Advancer is too focused on showing values.  Instead, we want to design our agreements to let us best describe the most common kinds of hands.  In this auction, Advancer having lots of values is not common.  Let’s see how using redouble as a conventional bid, called a Rosenkrantz Redouble, can be more effective than this traditional value-showing redouble.

Rosenkrantz Redoubles

When partner overcalls, they frequently will have holdings like:

• AQxxx

• Axxxx

• KJxxx

• Kxxxx

With holdings like these, partner will be worried about leading their suit.  If we have a top Honor (Ace or King) in their suit, then partner should lead their suit; but if we do not, then leading their suit could be costly.  In this case, it would be very helpful if Advancer had a way to show a top Honor in partner’s suit.  This is what a Rosenkranz Redouble accomplishes.  When Responder makes a negative double, then Advancer can use this special redouble to show either the Ace or King in partner’s suit.

Example 1

Opener                Interferer            Responder          Advancer
1♣                          1♠                           X                             XX*

This redouble (Rosenkrantz) shows either the ♠A or ♠K.  It could be holdings like

• Singleton A or K

• Doubleton A or K – Ax, Kx

• Axx

• Kxx

Note:  Some partnerships may agree that this redouble shows both a fit and a high honor (Ace or King), but this makes the redouble less frequently useful. 

This is a very useful agreement because when Advancer does not make a redouble, then Interferer is alerted to the fact that partner does not have a top Honor and that it may be dangerous to lead their suit.

Example 2

Opener                Interferer            Responder          Advancer
1♣                          1♠                           X                             P

This pass by Advancer implies they do not have the ♠A or ♠K and Interferer should be careful leading their suit.

When Advancer raises Interferer’s suit in these auctions then there is an inference that Advancer does not have the Ace or King.

Example 3

Opener                Interferer            Responder          Advancer
1♣                          1♠                           X                             2♠

Playing Rosenkrantz redoubles, this raise to 2♠ shows at least 3-card support and denies having either the ♠A or ♠K.

Opening Leads

Another way that the Rosenkrantz redouble can help a partnership is to get them a ruff early in the auction. 

Example 4

Imagine defending a 4♥ contract with this layout in the ♠ suit.

♠ Txx

♠ Axxxx                ♠ Kx

                ♠ QJx

Opener                Interferer            Responder          Advancer
1♣                          1♠                           X                             XX*
2♥                           P                             4♥                           All Pass

If this is the auction, then West knows it is safe to lead a low ♠ because they know that partner has the ♠K.  With a low ♠ lead, the defenders can take the first three tricks – ♠K, ♠A, and a ♠ ruff.

Note:  Some partnerships also choose to play Rosenkrantz doubles instead of snapdragon doubles in auctions where Responder bids a new suit – showing Ace or King in partner’s suit.

Conclusion

A Rosenkrantz redouble helps partner with an opening lead by showing a top honor with a redouble (or even more importantly denying one when a redouble is not made.)  This gives up a natural redouble (showing values), but this is not a very common bid by Advancer in this situation.  If you and partner like “practical gadgets” that help you communicate in difficult competitive auctions you may find this useful.  Discuss using this gadget with your regular partners.