Interfering With Their Notrump

When they open 1N, they will get to a good contract a great deal of the time if left to their own devices. The reason we say “systems on” is that it is indeed a system. It is a machine designed to work very precisely. We need to throw some sand in their gears.

In Bidding Notes and Defensive Bidding I give a great number of choices for interfering conventions and that’s out of an even greater number that exist! But in 2016, a convention became legal that is relatively easy to learn and yet hard to cope with (which is why it wasn’t legal before). This convention is called Multi-Landy.

If you want to learn one of the more standard defenses, D.O.N.T is what I would recommend, because it is oriented toward interference as often as possible, which is what 99ers need to learn to do, and is not excessively complicated.

The requirements to bid are pretty much the same for all these methods. You should have 8+ HCP concentrated in your suit(s), or maybe 10 HCP if vulnerable. There are no hard and fast rules, but better shape is an excuse for more bidding. They have the high cards, you need the shape. For two-suited bids, 5-5 is best, and six cards for one-suiters. Depending on the intermediate cards, concentration of honors, vulnerability (in short, all the usual suspects), you can go to 5-4 for two-suited and 5 cards for long suits.


After they open 1N, or optionally in fourth seat after (1N) - P - (P), here is a simple version.

  • 2♣! shows both majors. You should be 5-5 or 5-4 in the majors, with your points in those suits. 2♦ by advancer shows equal majors and asks intervenor to choose.
  • 2♦! shows an unspecified long major suit (could be five cards but usually six or more).
  • 2♥! shows five+ hearts and an unknown 4-card minor.
  • 2♠! shows five+ spades and an unknown 4-card minor.
  • 2N is unusual two notrump, promising 5-5 in the minors.
  • 3 any suit is natural.
  • X is a partnership choice. Various versions exist, but a simple way is to play this as “equal hand”, showing a hand as good as the opener’s range, penalty-oriented.

Other approaches to this class of conventions try to use the double to show hands with a four-card major with a five-card minor, or multiple hand types.

Your partner is off the hook if opener’s partner bids. He should only bid then with values. Otherwise:

  • After 2♣, he bids his best major.

  • After 2♦, he bids 2♥, which you pass or correct to spades.

  • After 2♥ or 2♠, he passes or if certain he cannot tolerate that suit but can tolerate your minor, bids 2N!(tell me your minor).

  • Once a year, max, he can disobey and bid his own suit, typically a good seven-carder or the like.

  • After a double, partner passes if he wants to penalize. If they run, a second double by our side is takeout, and a third is penalty. We should not pass their contract below two spades.

    Partner can bid a suit if he doesn’t want to sit for the penalty.

The goal is to learn to get in there and bother them, and help our defense. If you don’t bother them, they are very likely to get to a good contract. Sure, once in a while you get burned, but remember, over time, they are going to get very good scores if you do nothing.

What About Weak NT?

If they are playing an opening NT weaker than 15-17, you simply up your aggression level. The double means a hand as good as theirs; and you can also lighten up on your shape requirements, perhaps considering two good four-card suits as worth bidding. It is now much less likely that this is their hand than when they open 15-17.

Advancer must adjust his behavior after a double. Partner no longer is promising a big hand. If he has a bigger one than promised, he can bid on.

In Fourth Seat

If they opened 1N and your partner in second seat was unable to interfere, then it takes a little extra for you to come in because the big hand is behind you. However, it is often possible to double an artificial response to the 1N, such as a transfer. This double is lead-directing so you want to do it when you want the lead in the suit bid. You have to have a good enough hand and especially good enough suit so that you could survive it if opener decides to sit for the double. You don’t have to make, but you’d want to be close. Most of the time the opponents are going to go on, but your partner will know what to lead.

Remember, and double of an artificial bid is lead-directing. The same applies to artificial replies to Ace-asking bids, for example.