There are two general categories of systems against the opponents 1NT opening bids – ones that use a Double as Penalty and others that use a Double as conventional.  When the opponents open the bidding with a weak 1NT we need a good method for dealing with their unusual opening bid.  The most common range for a weak NT is 12-14 points, but we define 1NT to be weak if the range does not contain 16 points.  Some examples:  10-12, 11-13, 11-14, 12-14, 12-15, or 13-15 points.  Against these opening bids we use a system that has a penalty double. Let’s look at one fo the most interesting of these sysetm, Landy with Transfer bids.

When partner opens the bidding in a suit at the 1-level and the next player overcalls 1NT, we want to have a system that allows us to deal with this interference effectively.  With a good hand (which is somewhat rare in this auction), we make a penalty double.  With a poor hand that is relatively balanced, we likely want to stay out of the auction and simply pass.  It is the distributional hands with some values, but less than 10 HCP, where we are likely to want to compete in the bidding.  One way to make it easier to bid with these distributional hands is to use a system similar to what we do when the opponents open 1NT.  Let’s look at what systems we should use in these auctions and how our system varies based on which suit partner opened.