The 1NT response is constructive in 1♣-1NT or after an overcall. Such 1NT requires 7+~10 HCP, balanced distribution, and a stopper in the adverse suit if the overcall shows one suit. This response still denies a biddable major suit because major contracts are often better.
The 1NT under these circumstances are constructive because there are more suitable calls for 6~7 HCP hands. For an 1♣ opening, responder can always bid a suit with these weak hands. After an overcall, responder can pass because this pass will not cause a passing out.
A delayed raise shows game-forcing values by intentional violation of contract seeking rules. Such a raise must be at least 3-level to leave 2-level raises as natural suit preference. If a delayed raise is under game in an already game-forcing auction, the raise starts a slam try.
This mechanism saves bidding space for strong hands. This treatment, which conforms fast arrival and useful space principles, is rather necessary for a decent bidding system. The same reason applies to also cuebids and takeout doubles.
- 1♣-1♥; 1NT-3♣
- This is a delayed raise. With an invitational hand, responder bids Roudy 2♣ instead.
- 1♣-1♥; 2♣-3♣
- This is a usual invitational raise because the fit may be newly found.
- 1♦-2♣; 2NT-3♦
- This is a delayed raise showing slam interest.
- 1♦-2♣; 2♦-3♦
- This is a simple announcement of fit to give a chance to stop at 3NT.
- 1♦-2♣; 2♦-4♦
- This is a delayed raise showing slam interest because minimum is shown by 3♦ or a direct game.
- 1♠-2♣; 2♠-4♠
- This is a normal delayed raise showing real values, freeing 1♠-4♠ as a preempt.
- 1♠-2♣; 2♠-3♠
- This is a delayed raise showing slam interest because minimum is shown by 4♠.
The 1NT response in 1♠/♥/♦ (pass) 1NT is dustbin, which shows a constructive 1NT or 6~10 points without another suitable call.
In a constructive auction, a pass to 1 of a suit can only be made from a hand with < 6 points to prevent a loss of game. However, bidding on the 2 level shows at least invitational values. Therefore, responder holding a suit lower than the opening has to bid 1NT with a minimum responding hand.
A legitimized psychic Stayman with a weak 3~4♠ 3~4♥ 4~5♦ 0~1♣. Responder passes opener's most frequent rebids viz 2♦, 2♥, 2♠.
Lebensohl is a conventional puppet bid 2NT after an intervened 1NT opening. This convention is also applied after a takeout double over an opponent weak 2. Usually the captain bids 3♣ relay and the puppet then rebids at 3-level. This convention effectively duplicates 3-level bidding space at the expense of the possibility to stop at 2NT.
Wbridge5 Lebensohl implementation is very different from the outside world. Our Lebensohl accepts 4-card suit but shows exact invitational strength over 1NT. There are also other deviation from the commonly used Lebensohl.
The relayer, who bids the relay, becomes the captain. The captain provides little information and makes the final decision. The captain's parter is the puppet, who describes hand when the captain asks.
Roudy (aka Roudi) is a club relay to ask notrump bidder's strength and length of captain's suit. The puppet answers artificially in short-long-long-short coding. This convention is in place of Checkback Stayman.
The short-long-long-short coding which not only helps find suit contracts but also occasionally leads to an optimal 3NT signoff. The short answers indicate the minimum length, 2 cards for opener's notrump rebid, 3 cards for a puppet special 2NT.
This convention is popular in France, its origin. Originally, this convention is *-*; 1NT-2♣. Wbridge5 generalizes it to some *-2NT-3♣ auctions. The notrump bids in these auctions are somewhat natural, which sets reasonable minimum length of every suit.
- 1*-(non-♣ new suit); 2NT-3♣
- 1M-2NT; 3♣
The 1NT response to a major opening is semiforcing. The actual convention is opener's 2♣, which is biddable with only 3 clubs if RHO did not overcall.
The 1NT is still semiforcing even if the major opening is intervened, i.e. such intervention only affects responder.
Strong jump shift
Jump to a new suit over 1-of-a-suit opening in a constructive auction, showing 17+ points and 4+ cards. This is an important constructive slam bidding tool. Wbridge5 SJS is more aggressive than Soloway jump shift.
Side suit restriction like Soloway only applies to 3♦/♣ because 2/1 better handles the side suit. Bergen raise is also employed in Wbridge5, so the only Soloway-restricted jump shift is 1♦-3♣, but Soloway rebids are still never used.