The 12 Habits of Highly Effective Bidders   (July 2012)

10.  They allow their opponents to make mistakes. 

Just when you thought you were having a winning session, two experts arrive and steal a board by responding with a 2-point hand. You collect a small penalty, but their overbidding shuts you out of the auction and you miss your laydown game.

If you've ever been burned by this tactic, you may be wondering if it's become hopelessly old-fashioned to require six points for a response to an opening suit bid. Since bidding with no points and no fit seems to work so well against you, should you adopt the same strategy?

Sub-minimum responses are gaining popularity in part because they're so disruptive. They use up bidding space, which makes it more difficult for the opponents to find their best contract, and they often cause the opponents to misjudge their combined strength. 

The downside is that ultra-weak responses can also mislead partner and propel your auction too high. If partner opens 1C and you respond 1S with
   J653   Q74   8763   J2
the odds of a good result may depend on the opponents' bidding. If they pass, your best hope is that partner has four spades and raises only to 2S -- and that you don't go down more than two tricks (or one trick if vulnerable).

If you want to take advantage of the obstructive potential of light responses, it's best to have a constructive purpose,  too. One goal is to find a better partscore. Another is to get to a short-point game. Either is a possibility if partner opens 1C and you respond 1S with
   K10932   5   8642   743

If partner raises spades to any level, you expect to make your contract. Over a notrump rebid, you can get to a spade partscore. If he rebids anything else, your dummy won't be a total disappointment. And if it happens to be the opponents' hand for a heart partscore or game, your bold bid will force them to start looking for it at a higher level -- or perhaps silence them.

A weak response may also be justified when you're desperate to get partner out of his suit. If he opens 1S, you might consider a forcing 1NT with
   Void   1065   Q1082   986543
You've made a great decision if partner rebids 2C, 2D or 2H. On a bad day, he'll raise notrump or bid more spades and you've turned a bad contract into a terrible one, but that's a gamble you were willing to take.

When considering a new-suit or 1NT response with a sub-minimum, look for a good combination of these conditions: 

   2012   Karen Walker