Bridge Buff plays a large number of popular conventions. Most of these you can switch on or off. You can also play separate conventions for North-South and East-West. Browse the list to the right of this page.
After an artificial strong 2 opening, a 2 response is a 'waiting' bid and can be very weak (often) or possibly strong with no outstanding suit to bid. Opener and responder clarify their holdings on their rebids.
Flannery is a 2 opening bid which shows 5 hearts and 4 spades. 2NT asks for more details. 3 shows a 4/5/1/3 or 4/5/0/4 hand. 3 shows a 4/5/3/1 or 4/5/4/0 shape. 3 shows a weak 4/5/2/2. 3 shows a strong 4/5/2/2. 3NT shows a strong 4/5/2/2, with stoppers in the minors. There is a special defense to this convention.
Roman 2 bids are available in 12-15 and 17-20 ranges. They show 3-suited hands (4/4/4/1 or 5/4/4/-) with unspecified shortness. To find the shortness, responder bids 2NT, and opener bids his short suit
After a Weak 2-Bid, responder can query opener with 2NT for aces or kings in lower-ranking suits. After 2/2NT, responder bids 3 with the diamond ace or king. This treatment is useful when probing for a stopper for a notrump contract.
After an opening
bid of 1NT, responses of 2 shows hearts, and
2 shows spades.
Additionally, you can play that 2 shows clubs, and 2NT shows diamonds,
usually in a weak hand.
This means that with an invitational balanced hand you cannot use 1NT-2NT as a direct raise, and you must start with a 'phantom Stayman 2, then rebid 2NT, even if you do not have a four-card major.
An opening bid of 1 or 1 must be at least 5 cards long. You may open in a minor suit with as few as 3. Open 1 with xxxxx/AKJx/AKQ/x, and 1 with AKxx/AKxx/xx/xxx. Used with the Forcing 1NT, See also Constructive Raises, Bergen Raises, Cue Raises, Jacoby 2NT, Jordan 2NT, Limit Raises, Preemptive Jump Raises.
This is a system of responses to an opponent's opening bid of 1NT. 2 = hearts and a minor suit. 2 = spades and another suit. Other bids are natural. Overcaller might bid 2 with xx/KQJxx/KQxxx/x or 2 with QJTxx/x/xx/KJTxx.
This is a simple system of responses to an opponent's opening bid of 1NT. Dble = same range. 2 = both minors. 2 = both majors. Others bids are natural. Overcaller might bid 2 with KQTxx/QJTxx/x/xx with vulnerability favorable.
Bergen Raises are preemptively-based major suit raises. With 4 trumps after a 1 opener, responder will bid 3 with 8-9 HCP, 3 with 10-12- HCP. With less than 7 HCP, and shortness, responder will bid 3 (Kxxx/x/xxxx/xxxx). With 12+, force with Jacoby 2NT. With less than 7 and no shortness, bid 2. With 3 trumps, bid normally. See also Constructive Raises, Cue Raises, Jacoby 2NT, Jordan 2NT, Limit Raises, Preemptive Jump Raises.
Blackwood is a 4NT bid asking for aces. Responder bids 5 with 0 or 4, 5 with 1, 5 with 2, and 5 with 3. A following 5NT asks for kings, but is never bid without partnership possession of 4 aces. Cue-bids are preferable to Blackwood if there is a possiblity of you missing both the ace and king in a suit. See also Roman Keycard Blackwood.
This is a system of responses to an opponent's opening bid of 1NT. It revolves around the heart suit. Dble = some one-suited hand. 2 = hearts and clubs. 2 = hearts and diamonds. 2 = hearts and spades. 2 = spades and a minor. 2NT = both minors.
Cappelletti is a method to describe various kinds of hands over a 1NT opener. Double is for penalties. 2 is a 1-suited hand. 2 = majors. 2 = hearts plus a minor. 2 = spades plus a minor. 2N = minors. This is probably the most popular system, although it is deeply flawed. See MONK for a far better method, we think.
After opener's xNT rebid, responder can investigate opener's major-suit holdings. Opener (1) bids an unbid 4-card major, or (2) shows 3-card support for responder's bid major, or (3) bids diamonds. Similar to New Minor Forcing.
This is an attempt to narrow the 5-9 range of the normal 1 Major - 2 Major sequence. After a 1 opening, playing Constructive raises, responder shows the 5-7 range by first bidding 1NT Forcing, then rebidding 2. He shows an 8-9 range by directly bidding a constructive 2. The disadvantage to this method is that opener cannot know, after a 1NT response, whether the 2 bid is simply a preference with 2 spades, or a 'real' minimum raise with as many as 4 spades. See also Bergen Raises, Cue Raises, Jacoby 2NT, Jordan 2NT, Limit Raises, Preemptive Jump Raises.
These are bids that show controls (aces and kings) in the bid suits, usually used to probe for slam. Holding say AKxxxx/AKxx/xx/A, opener starts 1 and partner offers a limit raise to 3. There are clearly excellent chances for slam, but it would be dangerous to launch Blackwood holding a small doubleton club. Opener should bid 4 a cuebid, hoping that partner can show a diamond control. If he cannot, opener should be content with game. Responder might have either QJxx/QJx/Qx/KQJx (no slam) or QJxx/QJxx/AKx/xx (grand slam).
In competitive sequences, responder cuebids an opponent's bid to show a limit raise or better in opener's major. This treatment is also used on defence. A jump raise in competition is therefore preemptive. After 1/2, 3 is preemptive, maybe holding x/QJxx/xxxxx/xxx, and 3 shows a limit raise or better, maybe holding x/QJxx/AKJxx/xxx.
Stands for Double Openers NT. After an opening 1NT, double shows a 1-suited hand, and a bid of a suit shows that suit, plus a higher-ranking one. 2 is natural.
DOPI is acronym for "Double with 0 (none), Pass with 1". DEPO is "Double with Even, Pass with Odd". Then bid up-the-line. Used if opponents interfere with your Blackwood query.
Sometimes opener will open in third or fourth seat with skinny values. Drury is an artificial 2 response that can be used by responder to check if opener had full values for his MAJOR suit opener. It was devised by Doug Drury, a Torontonian, to protect himself against the outrageous third seat openings of his partner, Eric Murray.
With normal Drury, after 1/2//?, opener bids 2 to show substandard values (perhaps he opened 1 with KQJxx/Axx/xx/xxx) and another bid would show a legitimate opener. Using Reverse Drury, opener rebids his suit to show the substandard holding. Responder, a passed hand, will normally have a fit with partner's suit, and limit raise or better values.
Another variation is 2-Way Reverse Drury, which uses 2 to show 3-card trump support, and 2 to show 4-card support. Opener rebids 2 of his suit to show a sub-minimum, and any other suit to show a standard or better opener.
After a major suit opener, responder can show a hand with four trumps and a side suit in an invitational raise. Responder might bid 3 after a 1 opener holding Jxxx/x/xxx/AKJxx.
In a game-forcing sequence, a fast jump to game is not as strong as a slower route to game. This approach creates more room for slam exploration.Consider the auction 1/2//2/?? where the 2 response was game forcing. If responder bids 4H, it shows a weaker hand than 3.
Flannery is a 2D opening bid which shows 5 hearts and 4 spades. 2NT asks for more details. 3 shows a 4/5/1/3 or 4/5/0/4 hand. 3 shows 4/5/3/1 or 4/5/4/0. 3 shows a weak 4/5/2/2. 3 shows a strong 4/5/2/2. 3NT shows a strong 4/5/2/2, with stoppers in the minors. There is a special defence to this convention, see below.
Flannery is a 2D opening bid which shows 5 hearts and 4 spades. Overcaller defends as follows: 2 is like a takeout double of hearts, which shows the other three suits; 2/3/3 are natural; 2NT shows the minors; double shows a strong NT hand.
Responder's 1NT to an opening major is a 1-round force. Playing two over one, the bid can have as many as 12- points, and can show a variety of hands. Opener rebids his suit with 6+, or shows a 2nd suit (4+ hearts, or 3+ minors). He jumps to the next level with these shapes and 18+ points.
A variation of this is called a "Semi-Forcing" 1NT. Using this, opener can pass the 1NT response with 5332 shape and a minimum hand, up to about a bad 15 HCP.
Playing Forcing Stayman (2-Way Stayman), 2 is non-forcing, and 2 is game-forcing. Opener bids 2 with 4 hearts or both 4 hearts and 4 spades, 2 with 4 spades, 3/ with 5 in the suit, and 2NT with none of the above.
In an uncontested auction, if responder bids the fourth suit, that is a bid of convenience, it is forcing to game, and it says nothing about the suit bid (however often responder will hold 2 or 3 small in it). For example reponder holds Axx/Kxxx/xx/AKxx and the auction proceeds 1/1//1/?. Responder has enough to force to game, yet no bid is suitable. He cannot bid notrump without a diamond stopper, he can't support partner. An artificial 4th Suit Forcing bid of 2 stands out.
Gerber is a 4 ace-asking bid, like Blackwood. Gerber is only used when partner's preceding bid was some level of NT, and it is always Gerber when bid in that sequence. Responses are 4 =0 or 4 aces, 4 = 1 ace, 4 = 2 aces, and 4N = 3 aces. 5 goes on to query kings, with similar responses.
A growing trend is to open 1NT instead of 1 with a balanced hand like AQx/KJxxx/Kx/QJx. Usually this opening is reserved for 5/3/3/2 hands although some partnerships might include appropriate 5/4/2/2 hands. There is substantial evidence that a 5-3 major suit fit, with both hands balanced, will usually play as well in notrump as in the major. Responder, if he holds a 4-card major, will usually use Stayman to check opener's major-suit holdings, so a 5-4 fit will be found.
This is often used with Puppet Stayman, which permits responder with an unbalanced 3-card major holding to check for a 5-card major in opener. Responder might hold x/Kxx/Axxxx/Kxx for example, and want to play in a 5-3 heart fit if it exists.
Playing this, the meanings of 1/2 and 1/3 are reversed. 1/2 shows 4+ trumps and 10+ points, whereas 1/3 shows a weak, preemptive hand and 5+ trumps. The same holds true after a 1 opener.
This is a forcing major raise with 4 trumps, and 12+ points. Opener (1) bids shortness at the three level (2) bids a 2nd 5+ suit at the 4-level (3) bids 4M/3N/3M with a minimum/good/excellent hand (bids less with more). See also Bergen Raises, Constructive Raises, Cue Raises, Jordan 2NT, Limit Raises, Preemptive Jump Raises.
These bids are made by responder after an opening xNT bid. They are often used by strong notrumpers so the 'good' hand will be hidden during play. 2 transfers to hearts, and 2 to spades. A direct 2 by responder shows a weak minor 2-suiter. Compare with 2-Way Stayman also called Forcing Stayman.
If partner opens a major (say ), and overcaller doubles, you bid 2 with a minimum hand, 3 preemptively, and a Jordan 2NT as a limit raise or better. XX in this position shows 10+ points, and tends to deny opener's suit. See also Bergen Raises, Constructive Raises, Cue Raises, Jacoby 2NT, Limit Raises, Preemptive Jump Raises.
After an opening bid of 1, there is an advantage to switching the 1 and 1NT (forcing) responses. This is called the Kaplan Interchange. Suppose responder does NOT have spades but does have a typical 1NT force. Playing standard responses, you cannot play in 1NT, because that bid is forcing. However if you play the Kaplan Interchange, responder bids 1 with those hands, and opener with most minimum 5332 hands can now rebid 1NT to play, if responder agrees that is a good spot.
The disadvantage is that when responder DOES have spades he must bid 1NT which bid is forcing, so the partnership cannot play 1NT (with normal methods they can, with opener rebidding 1NT ... 1-1//1NT).
However the advantage outweighs the disadvantage, because responder will NOT have spades more often than he will have spades, so you will be able to settle in 1NT more often.
The terms Roman Keycard Blackwood (RKB) and Keycard Blackwood are both used. There are two version of RKB. Instead of asking for aces, 4NT asks for key cards. A key card is an ace, OR the king of trumps, so there are 5 key cards in total.
After 4NT, one version is called 0314 KCB. A response of 5 shows 0 or 3 key cards, and 5 shows 1 or 4 key cards. You should know what the actual number is using bridge logic and looking at your hand. Another version is called 1430 KCB, where the meanings of 5 and 5 are reversed. There are technical reasons for slightly preferring 1430, but there are holdings and situations where 0314 works best, so use whatever is most comfortable for you.
After a 5 or 5 reply, the 4NT bidder can then ask for the trump Queen by bidding the next higher suit. A response to that of one-level higher denies the Q, and a response two levels higher confirms the Q. In the auction 4NT/5//5/5, playing 0314, 5C says 0 or 3 key cards, 5 asks for the Queen of trumps, 5 denies it. In the auction 4NT/5//5//5 playing 1430, 5 says 1 or 4 key cards, 5 asks for the trump Queen, 5 says 'I have it'.
Using either 0314 or 1430, a response of 5 shows 2 (or 5) key cards
without the trump Q, and 5 shows 2 (or 5) key cards with the trump Q.
You can ask for number of Kings by bidding 5NT. Since the whereabouts of the trump King should be known, there are only three outstanding kings. Responses are 6 = 0, 6 = 1, 6 = 2 and 6 = 3.
Over an opening 1NT bid, an overcall of 2 shows the majors. Other bids are natural.
Lebensohl is a system of responses when opener bids 1N, and overcaller interferes at the 2-level. Responses at the 2-level are to play. Bids at the 3-level are forcing. 2NT is a relay to 3. A 'fast' jump to game denies a stopper in the bid suit; whereas a 'slow' sequence, starting with 2NT, shows a stopper. See also Negative Doubles in this position.
After overcaller has doubled a weak two bid, it is useful for advancer to be able to tell overcaller if his bid shows values. For example, after a 2/X/P/? auction, advancer might be weak with xx/QJxx/xxxx/xxx and be forced to bid 3, or he might have quite a decent hand with xx/KQxx/Axxx/xxx and be happy to bid 3.
Overcaller is forced to guess which hand advancer might have. Advancer can use an artificial Lebensohl 2NT bid here to show a weak hand. The doubler is forced to bid 3, and advancer can then pass (with a weak club hand) or bid his suit ... in our example with xx/QJxx/xxxx/xxx he would bid 3. That complete auction would be 2/X/P/2NT//P/3/P/3.
Lebensohl is invoked if advancer has less than about 8 points. With more than 11 or so, advancer will try a game, so the direct 3-level suit bid is in the 8-11 range. With xx/KQxx/Axxx/xxx advancer bids 3 over the takeout double.
After a major suit opening, a limit raise has11-12- points, with adequate trump support. After 1, bid 3 with 4 trumps, with Kxxx/Axxx/Axx/xx. With 3 trumps, with Kxx/Axxx/Axxx/xx, start with a forcing 1NT, then rebid 3. See also Bergen Raises, Constructive Raises, Cue Raises, Jacoby 2NT,, Preemptive Jump Raises.
This is a defensive bid, usually showing a weak two-suited hand. A cuebid of opponent's major suit shows the other major, plus a minor. A minor-suit cuebid shows both majors.
Much of the non-North American world plays 2 as a multi purpose bid. It shows a Weak Two Bid in EITHER hearts or spades, OR some kind of strong hand, often a big 3-suiter. The Bridge Buff variety limits the meanings to just the weak two bids. After opener opens 2, if responder has length in only one major, he should tread carefully because usually opener will have his shorter major. Here are the responses that Buff uses.
2 is pass or correct to 2. 2 is pass or correct (and shows heart interest). 2NT asks for clarification (3 is strong 2, 3 is strong 2, 3 is weak 2, 3 is weak 2). 3/3 are natural. 3 is preemptive in BOTH majors. Others are natural.
There are many many defenses to the multi opening. Bridge Buff uses a very simple natural one. Double shows 13-15 (or 19+) both majors stopped. 2NT shows 16-18 both majors stopped. All suit bids are natural.
This is an offensive bid that shows the unbid suits, rather like a takeout double by the defenders. Most low-level doubles are negative doubles; rarely they are responsive. It is not so important that the unbid MINOR is the proper length. Here 1/1/X shows four hearts, but doesn't guarantee diamond length. In the common sequence 1/1/??, most play that Double shows four spades (with almost no consideration of club length), and a 1 response shows five or more spades.
Playing Weak (12-14 HCP) Notrumps, it is sometimes useful to be able to use a negative double after a natural overcall of 1NT.Of course, it is sometimes useful to be able to use a penalty double as well, so the partnership will have to decide which treatment is more useful. After 1N/2, playing negative doubles, responder might double with say QTxx/xx/ATxx/QJx, looking for a partial. If opener holds good hearts, he can choose to pass and defend.
The auction has been 1 - 2 - ?? to you as responder. You hold KQTxxx/xx/xxx/xx. Using standard methods responder needs about 10 or so HCP to bid 2 in this position, so that bid is out, leaving a negative double as the only alternative (or pass). After the double you hope to be able to get back into the auction at a later point to show your spades. However sometimes the opponents will preempt and make it difficult and dangerous for you to bring them in later.
Playing Negative Free Bids, you are allowed to bid 2 directly with that previous hand. A 2 response would show about 5 to 11 HCP. The illustrated hand is about as weak as the bid should be.
Now you might wonder what one does with a GOOD 2 bid holding maybe KQTxxx/xx/AKx/xx. With that hand, you make a negative double. Now when you bring spades into the picture later in the auction, it is far safer to do so, and opener will treat your spade bid as game-forcing, showing 12+ points.
Playing Negative Free Bids, you also make 'standard' negative doubles, so if responder held say Kxxx/xx/KQxx/xxx, he would still double. The double does not promise a big hand ... the big hand is revealed later in the auction, after the double, when responder bids his suit.
After a NT rebid, responder can force opener to bid again by bidding the unbid minor; eliciting information about opener's major-suit holdings. See also Checkback Stayman. Opener's priorities are in this order: (1) shows an unbid four-card major (2) supports partner's major with three of them (3) denies either (1) or (2) with the cheapest available bid (which will be 2 over a 2 query, or 2NT over a 2 query).
A new suit by responder is forcing, even if it is lower-ranked than the first suit. Don't confuse this with Fourth Suit Forcing. Holding AKxxx/KQJx/xx/xx, responder can bid a forcing 2 in the sequence 1/1//2/??. The bid is forcing one round, not necessarily to game. Of course this means responder cannot bid 2 with a weak hand like Axxxx/QTxx/xx/xx, and must pass in this sequence.
In the majors, a jump raise in competition is preemptive. After 1/2/??, a 3 bid is preemptive, holding maybe x/QJxx/xxxxx/xxx. The same bid might be made as advancer in the sequence 1/1/2/??.
After a 1NT opener that could include a 5-card major, many partnerships use Puppet Stayman. If responder is balanced with a 3-card major, say xx/Kxx/Axxx/Kxxx, he probably will not bother to check if opener holds 5 hearts on the theory the hand will play as well in 3NT as in 4. However with say x/Kxx/Axxxx/Kxxx he will want to check.
After 1NT/2//? Puppet Stayman, opener bids 2 = no 5-card major, 2/ = 5 hearts/spades.
When opener bids 2, after 1NT/2//2/? responder bids 2 = 4 spades, 2 = 4 hearts, 2N = 4 spades AND 4 hearts.
After an opening bid, if you have a
4-card major and a 5/6 card minor, the major can be difficult to bid. Suppose you hold KJxx/x/xx/AQJxxx, and you hear
1 on your right. What are your options? You could bid
2, and likely lose the spade suit. You could overcall
1, but partner will expect more. You can double, but what will you do over partner's (expected)
2 bid? or his 3 bid if he has a decent hand?
The Raptor 1NT overcall solves that problem (while it introduces another). Raptor shows one 4-card major and one 5/6 card minor, with about 10 to 15 points. Over 1 or 1, it shows 5/6 in the unbid minor, plus a four-card unknown major. Over 1 or 1, it shows four cards in the unbid major, plus and unknown 5/6 card minor.
If you held KJxx/x/xx/AQJxxx, you would bid 1NT over an opening 1 (showing four in one of the majors, and 5/6 in clubs. Over an opening 1 you would bid 1NT showing four spades, and 5/6 in one of the minors.
You lose the normal balanced 15-18 notrump overcall. However those are fairly rare (Raptor will be much more common), and you can decide to pass with the lower of that range, maybe the 15-16 pointers, and DOUBLE then rebid NT with the higher part of that range.
Responses to Raptor are Pass/Correct (if advancer bids one of your suits, you pass, otherwise you bid the cheaper of your suits) 2NT is forcing and asks for the unknown suit.
If the auction goes 1 -1NT-P-??, overcaller shows 5/6 diamonds and one unspecified four-card major. Holding say xx/xx/QJxx/Qxxxx advancer would bid 2. If that was overcaller's major he would pass, otherwise he would bid 2.
If the auction goes 1-1NT-P-??, overcaller shows four spades and 5/6 in some minor. Advancer with xx/xxxx/KQx/Qxxx would bid 3, which overcaller would pass (with clubs) or correct to 3.
Playing Weak NoTrumps, it is useful to scramble effectively if Responder has a weak hand. Over an opponent's double, Responder passes if he wants to play there, with a 1-suiter he Redoubles forcing Opener to bid 2, with a 2-suiter he bids the lower of his suits, and Opener decides. This has similarities to DONT.
A double by advancer, after overcaller has bid, and after responder has raised opener's suit, is responsive, and shows the unbid suits, special attention being paid the majors. It is similar in nature to negative doubles, although not so common. In the sequence 11/2/??, a responsive double would guarantee four spades, and hint at some diamond length.
Roman 2 is a 3-suited hand with unspecified shortness. It is played in Weak (12-15) and Strong (17-20) ranges. Partner bids 2NT to ask for the short suit. With AQxx/KQxx/Kxxx/x open 2, and rebid 3 if responder queries with 2NT. Otherwise bids are 'pass or correct'. With Axxx/Kxxx/xx/xxx, responder bids 2 (he 'passes') over 2. If that is one of opener's suits, opener will pass. If opener has AQxx/x/KQxx/Kxxx, he will bid 2 (he 'corrects') over the 2 response.
After the auction 1/P/1/?, advancer might want to enter the auction with a shapely hand with length in both unbid suits, maybe here with KJxxx/x/QJxxx/xx. A Sandwich 1NT bid shows this kind of hand. A conventional takeout double would show more defence.
A takeout double in this position has more HCP and less shape, maybe a hand like this ... KQxx/Kx/AKJx/xxx.
After a 1NT opening, it can be useful for responder to be able to show a good hand with 5-4 majors. He first bids 2 Stayman, then after a 2 denial by opener, he jumps to the three level in his four card suit (so opener will be declarer if the partnership has a 5-3 major fit) .. this agreement being called Smolen.
Responder holds KQxxx/AQxx/xx/xx, and he bids 2 Stayman after partner opens 1NT. If opener rebids 2 to deny a 4-card major, responder jumps to 3. Opener holding AJx/KJx/AKxxx/xx can then choose between 3NT and 4, and holding a small doubleton club he chooses the 5-3 major fit. With AJx/KJx/Axx/Kxx he might choose to bid 3NT. Rarely, he opts for the 4-3 heart fit, perhaps with something like Ax/KJx/AKQxx/xx, on a hand where he judges the partnership might be off the first five+ club tricks in 3NT.
A 2 response to a 1NT opener, or a 3 response to a 2NT opener, is a major-suit query. Opener bids 2 with neither, 2 with both or hearts, and 2 with 4 spades. The probe is usually to find the right game, but it can be made with an invitational-strength hand.
A 2 opening is strong, artificial and forcing. It says nothing about clubs. Opener will describe his hand on his rebid. Opener may have a strong flat hand, in which case he will rebid some level of NT. Or he may rebid a suit. Responder will often (usually) respond with a Waiting 2D.
Suction is an increasingly popular defensive system to a 1NT opener. The suit bid shows either (1) the suit above it, or (2) the other two suits. 2 = diamonds, OR hearts and spades. 2 = hearts, or spades and clubs. 2 = spades, or clubs and diamonds. 2 = clubs, or diamonds and hearts. 2NT shows the other two-suiter possibilities, pointed diamonds and spades, or rounded clubs and hearts.
When overcaller has a one-suiter, Suction acts as a transfer and the opening 1NT bidder finds himself on lead.
Partner will almost always bid the next suit. If overcaller bids 2 (hearts or spades and clubs), partner will usually bid 2 which overcaller will pass or raise if he has hearts. If he has the two-suiter, he will bid 2, and partner will pass or raise or correct to clubs. Note if 2 is passed out, the NT bidder is on lead.
Used by opener to show exactly 3 trump support for responder's suit, whereas a direct raise shows 4 trump support. In the auction 1/P/1/1//??, 2 shows four trumps whereas double would show exactly three trumps.
A redouble can be used in the same manner. In the auction 1/P/1/X/??, 2 shows four trumps and the Support Redouble shows exactly three trumps.
After a major suit opener, these bids show 13-15 HCP and four trumps in a fairly balanced hand. 4 shows 2 of the top 3 honors. 4 denies 2 of the top 3 honors. After partner opens 1, bid 4 with QJx/AQxx/KQxx/xx and 4 with QJx/Axxx/KQxx/Qx.
Responder transfers to 4 with 4, and to 4 with 4, after an opening NT bid, hiding the stronger hand. Related to Jacoby Transfers.
In Standard American the sequence 1/2 shows as few as 10 points. Playing Two Over One, this sequence shows 12+ points and is game-forcing. The 10 to 12- point hands are often started with a 1NT forcing sequence.
A premptive NT overcall of a major, shows a weak 2-suited hand. It can be played as showing both minors only, but is more flexible as showing the two lowest unbid suits (both minors defaulted when a major suit is bid. Holding x/xx/KQxxx/QJxxx, overcaller bids 2NT over an opening bid of 1. Holding x/KQxxx/QJxxx/xx, overcaller bids 2NT over an opening bid of 1.
Bids of 2, 2 and 2 are usually played as 'weak', showing a 6-card suit and 6 to 11 or so points. Strong hands are opened with 2. 2NT asks for opener's side strength (A or K in lower-ranking suit).Open 2 with xx/KQJxxx/Kxx/xx.
Jump bids by defenders are usually weak hands with good suits.Over a 1 opener, overcaller might bid 2 with x/KJTxxx/xxx/xxx or 3 with x/KJTxxxx/xx/xxx.
A cue-bid in the opponent's suit in a competitive auction where no major fit is evident, is a request for partner to bid NT if he can 'stop' their suit.Holding say Kx/xx/AKJxx/AKxx, after the auction 1/P/1/2//?? opener might rebid 3 which would ask responder to bid 3NT with a heart stopper.