Opened 1NT

The 2NT is supposed to be too strong to overcall, so this is the only entry for competitive auctions beginning with strong notrump openings.

In a world of emerging defenses of 1NT, it is urgent to devise a set of counteractions. Luckily, Wbridge5 has come up with a good solution.

Although strategies may vary according to the overcall, there are 2 principles across all overcalls.

System off

There is no more Stayman nor transfers.

Catchall structure

Artificiality may introduce conventions but seldom changes bidding strcture.

Responses over (Dbl)

We have no conventional runout because 1NTx is often good enough. Opponents are worried about the double, too. Opener only runs to a suit with 5+ cards.

XX

Invitational+.

2♣, 2♦, 2♥, 2♠

Signoff, 5+ cards, too weak to invite.

2NT

Unusual, 5+ cards in each minor, too weak to invite.

Responses over (2 of a suit)

The cooperative double is not changed for artificial overcalls. This may be counterintuitive, but Lebensohl already takes care of the overcalled suit. It is better to still use the double to find a 4-4 fit.

Lebensohl is the only alertable convention here. Conventions at 4-level (4♦!, 4♠!) are cancelled because these 2-suiters can be expressed at 3-level first.

X

Cooperative double, invitational+, 2~4 cards in the overcalled suit, 3~4 cards in the other suits.

2 of a new suit

Signoff, 5+ cards, too weak to invite.

2NT!

Lebensohl, invitational strength, puppet to 3♣.

3 of a new suit

Game-forcing values, 5+ cards.

3NT

Signoff with all adverse suits stopped.

Cuebids

An adverse suit is a suit known to be held by opponents, aka an anchor suit. An overcall introduces 0~2 adverse suits. For example, Cappelletti 2♣ introduces no adverse suit, natural 2♣ one (♣), Landy 2♣ two (♠, ♥). A takeout is deemed suitless as a takeout double.

Cuebidding is to bid an adverse suit. Cuebids show game-forcing values but unsuitable to bid 3NT. Detailed meanings are introduced in the following subsections.

With 1 adverse suit

If the overcall is nonforcing, a pass may end the auction. Therefore, hands with more game aspect deserve a direct cuebid. The delayed cuebid denies stopper in the adverse suit, making it tolerable to pass out.

If the overcall is transfer, there may be 2 available cuebids below 3NT. The direct cuebid is mapped at 3-level, the delayed at 2-level, to achieve the same safety without passing out.

Direct 3-level cuebid

Takeout with game-forcing values, 4+ cards in every nonadverse suit.

Delayed or 2-level cuebid

Game-forcing values, adverse suit unstopped.

With 2 adverse suits

Because there are 4 possible stopper combinations, 3 cuebid patterns are needed to seek 3NT. The 2 direct cuebids shows the only stopped adverse suit. The delayed cuebid denies any stopped adverse suit, where passing out is tolerable.

Cuebid

Game-forcing values, stopper, the other adverse suit unstopped.

Pass then cuebid

Game-forcing values, both adverse suits unstopped.

Responses over (2NT)

The 2NT overcall is a cuebid and notrump contracts are hard to play, so this call is innately forcing. The force gives responder a second chance to bid, which makes up the loss of our Lebensohl 2NT.

The 2NT overcall usually shows both minors, which is not only practical but also logical. A convention skipping majors is usually minor-oriented, and 1-suited hands can be shown at 3-level.

The double seems useless. It dissuades opener from bidding, letting responder penalize opponents in the next round.

X

Invitational+, 4-3-3-3 in align with the cooperative double.

New suit

Game-forcing values, 5+ cards.

4♦!

Game-forcing values, 5-5 or 6-6 in majors.

In the next round

Unless vulerability is unfavorable, penalty is often better than 3NT if responder has strength but no biddable suit. If we can make 3NT, their 3-level contract often goes -3 or more.

X

Penalty

Cuebid

Game-forcing values, the bid suit unstopped.

New suit

Invitational, 5+ cards.

3NT

Signoff with all adverse suits stopped.

Responses over (3 of a suit)

The bidding structure is the same as competition on 2-level, but tactics are slightly changed. After an cooperative double, opener is reluctant to bid over 3NT. Therefore, doubling a major suit, especially 3♠, is more penal and off shape. Responder usually doubles 3♠/♥ instead of signing off at 3NT.

X

Cooperative double, invitational+, 3~4 cards in higher suits, 2~4 cards in the other suits.

3 of a new suit

Game-forcing values, 5+ cards.

3NT

Signoff with all adverse suits stopped.