The most important changes in OKb-style 2/1 as compared with OKb-style SAYC are:

1. Normally open five-card majors in all seats.

2. Open the higher ranking suit with 5-6 when the hand is minimal, and open the lower ranking suit when the playing strength (not necessarily HCP) justifies an invitational reverse on the next round of bidding.

3. Open the higher ranking of long suits of equal length: 5-5 or 6-6.

4. Normally open 1 with 4-4 in the minors.

5. Normally open 1 with 3-3 in the minors.

6. 1NT = 15-17HCP (NT openings show a balanced hand but can be made with a five-card major or minor suit).

7. 2NT = 20-21HCP

8. 3NT = Gambling solid minor (usually 7-carder) with no outside Ace or King

9. Strong artificial 2 Opener = 22+ HCP with a balanced hand. Unbalanced hands should have approx. 9+ playing tricks with at least 2 defensive tricks outside the long suit.

10. Weak two-bids in diamonds, hearts and spades = 5-11 Points, 6 card suit. A good quality trump suit (2 of the top 3 honours or close to that) is expected in 1st & 2nd seats (as a consequence of playing Feature Ask 2NT). In 3rd seat, the openings can be very undisciplined, especially at favourable vulnerability and at matchpoints.

2/1 GF applies only when our side opens 1 of a suit in 1st or 2nd position, the next player passes, and responder bids a new suit at the 2 level without jumping. Here are all of the cases:

• 1-2
• 1-2
• 1-2
• 1-2
• 1-2
• 1-2

Note:
A first round jump shift is not condsidered a 2/1 response: 2/1 refers to a non-jump bid of a lower ranking suit. Jump shifts retain their normal meaning. By an unpassed hand when RHO passes, a jump shift (as played in SAYC and OKb 2/1) shows a very strong hand and a good 5+card suit, usually a 6+card suit. Furthermore there is nothing special or different about it in OKb 2/1. The availability in OKb 2/1 of the NMF and 4SF conventions results in some auctions in which it is neither useful or necessary to jump shift with 17+ playing points on hands where one might consider it necessary to do so in SAYC due to a lack of good sequences after starting with a 1-level response.

Opener	Opp1	Responder	Opp2	Shows
1	Pass	2!-!-!	any	GF neither player can pass until game is reached, since the 2/1 bid is in a new suit. 1-2 shows 5+cards but 2 of a minor suit is often 4 (or even 3 cards, 3433 pattern), since J2N is used instead of a natural GF 2NT response
1	Pass	2!	3	GF unless opener or responser doubles which would be penalty double. After a 2/1, the opps cannot play undoubled, so passes are forcing if an opp made the last bid, obliging Responder to double for penalty or bid on.
1	2	2-	any	Approx 10+points. Not GF
1	1	2-	any	Approx 10+points. Not GF
1	1	2!	-?-	Weak jump shift - 6+ card suit, 0-6 points. Sign off not GF

Opener	Rebid Shows
X (in comp)	Penalty oriented
Pass (in comp)	Forcing Pass. Responder must X for penalty or bid on
Simple rebid	The catchall bid (a bid that covers all the remaining possibilities), does not promise extra strength or length
Jump rebid	Extra values, 6+card suit, solid or semi-solid depending on agreement. Responder's new suits are cuebids in support.
New suit at the 2-level	Natural, at least four cards, any strength
New suit at the 3 level (not a jump)	Natural, at least 4 cards, extra values (at least a king above min). This bid will be a minor suit. Requiring extra values helps responder gauge whether bidding past 3NT to explore a minor slam in safety. With minimum, bid 2NT if balanced/semi-balanced with stoppers, or rebid your major, the catchall. You may show the suit later if given an opportunity
Jump Shift to 3 level	Ambiguous. Depending on agreement, could be Splinter in support of responder, or a strong 5/5 with most of the strength in the suits. Avoid this bid with new partners
Jump Shift to 4 level	Splinter in support of responder
2NT	12-14 or 18-19 bal, stoppers in unbid suits. With 18-19, make slam try if responder signs off (e.g., natural 4NT after 1-2-2NT-3NT-4NT). Responder will assume 12-14 initially
3NT	15-17 balanced
Single raise of hearts	Any 3-card support, any strength. Not raising denies 3-card heart support. Denies hand appropriate for splinter or jump raise
Single raise of minor	Extra values, prefer 4 card or good 3 card support since responder often has only 4. The extra values help determine whether to bypass 3NT in search of slam. With min, bid catchall or 2NT and maybe show support later.
Jump raise	Most points concentrated in the 2 suits, denies control (A, K, singleton, void) in other suits.

Responder	Rebid Shows
2NT	12-14 or 18-19, stoppers in unbid suit(s). Could be unbalanced if no fit for opener. With 18-19, invite slam if opener signs off in game (1-2-2-2NT-3NT-4NT). Opener assumes 12-14.
Jump to 3NT	15-17, stoppers, could be unbalanced if no fit
Rebid 2/1 suit	Natural, 5/6+cards, forcing
New suit	Natural, 4+cards, or a cuebid if a fit has been established
Raise opener's suit	See section below

1. Since all bids below game are forcing, responder usually has many bids available to raise opener (3+card support if opener's first suit, 4-card support if opener's second suit). The concept of "fast arrival", jumping to game to show less strength than a lower raise, should only apply in situations when opener is usually minimum. This is when opener rebids 2NT or rebids his opening suit, the catchall. Thus:
   1-2-2NT-4 and 1-2-2-4 show a minimum GF hand with 3+ support.
   1-2-2NT-3 and 1-2-2-3 show more than a minimum, and ask opener to cuebid.
   
   
2. "Fast arrival" is not used in other situations, when opener could be any strength, because jumping to game would lose room to make cuebidsIn these other cases, a jump to game in opener's major is a "picture bid", showing points concentrated in the 2/1 suit and the major, and denying any controls (A,K,singleton/void) in the other suits.
   Examples of Picture Bid Sequences:
   1-2-2-4
   1-2-3-4
   1-2-3-4
   1-22-4
   
   
3. If opener has rebid 2 of a new lower ranking suit, responder has 3 raises available for opener's first suit:
   
   
   1. The jump raise to the 3 level is used to show extra values with good cards for a slam (1-2-2-3) and asks opener to cuebid

   2. Splinter - a jump in a new suit showing a singleton/void in that suit, and support for opener's last bid major, examples showing spade support and single/void diamond:
      1-2-2-4!
      1-2-2NT-4!
      1-2-3-4!
      
      
   3. If responder bids the lowest level raise, he just denies a hand appropriate for a Splinter or one of the jump raises.

The auction, 1-(P)-2

This auction is a special case, and is different from auctions that start 1 of a major. The opening bid did not promise 5 cards, and there is no 1NT! forcing available to responder. In many styles of 2/1 this auction is not played as GF. For OKb 2/1 however, the GF is "on". This is consistent with the treatment of 1-2NT as invitational with 11-12 points. The following set of recommended rebids is also consistent with that treatment, but do not expect a new partner to be on the same wavelength, as it is not Universal - accidents can be frequent!

Opener's Rebids after 1-(P)-2

Opener	Rebid Shows
2	5+, any strength, does not deny 4-card major
2NT	12-14,bal,stoppers, does not deny 4-card major
3NT	18-19,bal,stoppers
2-2	4-card major, denies 5+ unless major rebid on 3rd round to show a 5/6 hand. Does not promise extra strength

Note: Since 2 is a GF, what do you do with invitational hands? With a long 6+club suit, bid 1-(P)-3. This shows 10-12 points and is invitational, but non-forcing. It is no long a strong jump shift. With no long club suit, no 4-card major, and a hand that can't make an inverted raise of diamonds, bid 2NT, which shows 11-12 points. You will have to do ths on some hands that don't have stoppers in one or both major suits.

As a result of the 2/1 response being a "Game Force", responder will often have a 10-12 point hand with which he would like to make a 2/1 bid but cannot; hence the 1NT! Forcing convention. The 1NT! response to 1 or 1 shows 6-12 and is a one-round force. The 1NT! response denies a hand appropriate for a single raise or limit raise and, usually, over a 1 opener, denies 4 spades

Example hand types where the 1NT! forcing bid can be used systemically or tactically:

1. A hand with exactly 3 trumps and 10-12 support points that plans to jump in opener's suit over any rebid by opener.
2. Some players respond 1NT! with 3 card support and a poor 6-7 points in support in order not to overly encourage partner.
3. A hand with more than 2 card support but very weak approx 4-6 points, to discourage the opps from entering the auction.
4. Over an opener of 1, 1NT! usually denies 4+ spades, but is correct with a hand type of approx 5-9HCP, a weak 4 card spade suit, and a good 6+ card minor suit.
5. Some players respond 1NT! with a balanced hand that has more than 12HCP. This occurs most often with 13-15HCP and relatively weak holdings in the 4 card suit(s).

Sequence	Opener holds:	Opener's Rebid	Shows
1-1NT!	KQJT9 KJT6 A3 54	2	4+,appx 12-18 points,NF
1-1NT!	KQJT9 KJT A63 54	2!	3+,appx 12-18 points,less than 4 hearts,fewer clubs than diamonds,NF
1-1NT!	AQJT KJT98 Q6 54	2!	2+,appx 12-18 points, may have 4 spades, clubs equal or longer than diamonds.(the example hand is not strong enough to reverse).NF
1-1NT!	KT7654 AK3 6 AQ4	2!	2+, appx 12-18 points, less than 4 hearts, clubs equal or longer than diamonds:(in this example the spade quality is not good enough for a rebid.Opener hopes for another chance to clarify).NF

Sequence	Responder	Shows
1-1NT!-2	pass	6-9HCP
	raise	10-12 support points, 2 or 3 trumps, NF
	2NT	10-12HCP, less than 3 trumps,does not promise NT shape or stops, NF
	3xnew suit	10-12 points, v good 6+card suit, Invite
	raise to 4	10-12HCP, 3 of opener's major, NF
1-1NT!-2	pass	6-9HCP, usually 5+ in opener's minor, less than 2 of opener's major
	raise major	6-10HCP, usually 2 of opener's major,3 only if v weak, NF
	2x new suit	6-9HCP, usually 6+(or 5 good) in bid suit, less than 2 spades unless good new suit, NF
	2NT	10-12HCP,fewer than 3 trumps,does not promise NT shape or stops,NF
	jump shift	10-12 points, very good 6+ card suit, NF
	jump raise major	10-12 points, exactly 3 trumps
	raise minor	10-12 points, usually 5+ trumps
	4 of major	13+ points: a hand that increased in value after opener's rebid (includes 1-1NT!-2-4)

1. Jump Shift by Opener (example: 1-1NT!-3). Responder usually prefers back to opener's major with 2 card support (or bids 3NT with stoppers), even when holding good 4 card support in the minor. This is to conserve bidding space and allow for the likelihood that opener's second suit is short. With 3 card support in the major and 10-12 support, responder follows through on the original plan and jumps to game in the major.
2. 1-1NT!-2/-2: logically, this cannot be natural. A common agreement is for this to be an artificial raise of opener's second suit, showing 4+ support and invitational values. By extension, a raise of opener's minor changes in meaning to be 5+ card support and less than invitational. This approach can shut out the opponents and occasionally leads to thin shapely games or slams.
3. Partner opens 1, you respond 1NT!. Now partner rebids 2 or 2. You bid 3, which is TO PLAY. This is one exception to the normal rule where typically a new suit by responder is forcing. Here it is not. However, with say, Axxxx AQxx x Axx, another call by opener would be warranted since he has three-card support for responder's minor, a singleton in an unbid suit and both aces in the long suits.

Sequence	Responder holds:	Rebid	Shows
1-1NT!-2!	K43 98 KJ43 J432	2	Correct to 2. Don't pass
	K43 K98 AJ J9854	3	10-12 points.Exactly 3x,does not deny 4+.Invite
	T43 K8 QJ2 KQ876	3	10-12 Points 5+,denies 3x.Invite
	K43 A8 QJ32 T98	2NT	10-12 Points, gd stops in the unbid.Invite
	6 A53 52 AQT876	4	10-12 Points, 3x (hand has added value with dbl-fit).

A jump shift by responder in competition e.g., 1-1-2!, shows a 6-card suit and 0-6 points

2NT Response to Weak 2 Opener ( ! )

A 2NT! response over an opening Weak 2 is forcing and shows game interest (even if the opps intervene). Opener should show a "feature": ie. a suit with Ace or King. Rebid 3NT with AKQ in the opening suit. With no feature, rebid 3 of the suit.

Raise Only Non-Forcing (R-O-N-F)

A method of responding to weak 2 openers which utilises both 2NT! for feature, and a new suit as forcing response: hence, the raise of partner's suit is the only non-forcing response below game.

Unusual NT( ! )

1. A jump overcall of 2NT! over a 1 of a suit opener is Unusual NT and shows at least 5/5 in the lower 2 unbid suits. Overcaller's values can be very wide ranging, but should be concentrated in the long suits.
2. After a strong 2 opener, an overcall of 2NT! has the same meaning.

Note 1: Except 3NT, any other NT bid after both opponents have bid and partner has passed can also be considered as Unusual NT
Note 2: A 4NT bid over opp's opener of 1 of a suit should also be recognised as Unusual NT

Michaels Cuebid ( ! )

The Michaels Cuebid promises a 2-suited hand.

Opp1	O/Call	Overcall Shows
1-	2-!	both majors
1	2!	spades and an undisclosed minor
1	2!	hearts and an undisclosed minor

Note 1: A response of 2NT over the major suit cuebid asks partner to bid his minor
Note 2: In a competitive auction, if 2NT is unavailable, responder can bid 4 (non-forcing) or 4NT (forcing) to locate the minor. 3NT is always to play.
Note 3: The strength of the Michaels Cuebid follows the same guidelines as used for Unusual NT overcall. It is more "shape" than HCP that counts

Jacoby Transfers to Majors ( ! )

Jacoby transfers (Xfers) show a five+ card major suit:

2 is a transfer to 2
2 is a transfer to 2

Opener	Responder	Shows
1NT 2	2! Pass	Responder has 0-7HCP with 5+hearts
1NT 3	2! - ? -	Opener has 16+ support points and 4 hearts (invitational)
1NT 3	2! - ? -	Opener has 16+ support points,good club suit and 4 hearts (forcing)
1NT 2	2! 2NT/3	Responder has 8-9 HCP (invitational to 3N or 4)
1NT 2	2! 3-	Responder has 9+HCP, good side suit, but may not be long (GF, poss slam interest)
1NT 2	2! 3NT	Responder has 9+HCP asks Opener to pass or bid 4

Note 1: Jacoby Transfers are also used over openers of 2NT
Note 2: Jacoby Transfers are "off" altogether if the NT opening is overcalled.

Texas Transfers ( ! )

Jump responses of 4/4 over opener of 1NT/2NT to transfer to 4/4 when responder wants to be in game but has no slam interest

Opener	Responder	Opener
1NT/2NT	4!	4
	4!	4

The idea behind this convention is similar to that behind Jacoby Transfers - it is better for opener to be declarer, since his high cards won't be exposed to the defenders.

Using both transfer conventions, responding to both 1NT and 2NT, Root/Pavlicek recommend the following understandings:

1. Texas, then pass is signoff in game, therefore:
2. Jacoby, then raise to game is mild slam try (not forcing but opener is invited to bid again with maximum).
3. Jacoby, then 4NT is defined as quantitative slam invitation, therefore:
4. Texas, then 4NT is Blackwood.

Opener	Responder	Opener	Responder	Using both JXfer and Texas, Shows
1NT	2-!	2-	4-	Suggests slam interest
	2-!	2-	4NT	Quantitative slam invitation
	4-!	4-	Pass	Signoff in game, no slam interest
	4-!	4-	4NT	Blackwood, not quantitative

Texas Transfers are "on" in competition through 3 (see OKb 2/1 CC says "on /x"), i.e.,

Opener	Opp1	Responder	Shows
1NT	2-3	4!	Xfer to 4
	2	4!	Xfer to 4
	3	4	Natural, not an Xfer

Minor-Suit Stayman is just what its name implies: a device that allows a partnership to look for a minor-suit fit after an opening bid of 1NT (and over 2NT/3NT see note 2 below). Presupposing the use of Jacoby Transfers, the 2 response to 1NT is no longer needed to show spades and can be used to ask opener to bid a 4-card minor suit. The OKB 2/1 card uses a specific variant of MSS, which also includes weak hands with a long diamond suit, hence the notation “MSS or correct to or 3 with diamond bust”. This is a treatment that is part of the Walsh system. Other MSS variants may not include the weak hands that Walsh does, and have different response structures, so it may be best to avoid this bid in a new partnership.

2! response to 1NT(strong NT) shows one of three types of hands. It is either a weak hand with long (6+) diamonds,a weak hand with both minors (5-5), or a strong hand at least 5-4 or 4-5 minors with slam interest.(With both minors and only minimum values for game, bid 3NT. 9 tricks in NT is usually easier than 11 in a minor. Using MSS may pinpoint a weak major for the opponents to lead)

The 1NT opener should rebid:

1. 2NT = denies a 4 card or longer minor
2. 3 or 3 = at least 4 cards in the minor bid, bid the better one with both.

After using MSS and hearing any of the above rebids, responder's available rebids are:

1. 3! over 2NT = weak both minors, opener may pass or correct to 3 (e.g. xx x KJxxx QTxxx)
2. 3! over 2NT/3 = weak with long diamonds (x xx QJxxxxx Qxx
3. Pass over 3/ = content with contract, weak hand
4. 3NT = 2245 or 2254, slam invitational, non-forcing (xx Ax AKxxx KJxx)
5. Any major suit bid (!) = single/void in that suit, slam interest (3! with x Ax AKxxx KJxxx)
6. 4NT = Roman Key Card Blackwood if minor suit has been agreed but natural otherwise

Note 1: Minor-Suit Stayman (like Jacoby Transfers) is "off" altogether if the NT opening is overcalled. If the 2! response is overcalled or doubled, opener may:

1. pass with nothing else to say
2. double or redouble for penalty
3. make his normal bid

Interference after the 2! bid does not affect the MSS bidder.

Note 2: The use of MSS over 2NT, or 2-2-(2NT/3NT) is easily defined in that, if Jacoby applies, so does MSS, ie ., if a diamond or heart bid is Jacoby, then a spade bid is MSS. The use of MSS over 2/3NT always shows slam interest. If a minor suit has been agreed, then a later bid of 4NT is RKC, otherwise natural.

2nt->3 = club signoff, or 4441 (!)

Over opener's 1NT, a direct response of 2NT! is a puppet(relay) to 3! which responder can pass with clubs and a bust, or show a game forcing 3-suited hand, either 4441 or 4450 with a 5 card minor. With the strong hand rebid the suit containing your singleton/void. With short clubs, either rebid 3NT, non-forcing, or bid 4! with slam interest to force opener to bid.

Examples: after 1NT-2NT!-3!-?

1. Pass (x xxx Kxx QT9xxxx)
2. 3! ( AJxx x AKxx Qxxx)
3. 3NT! (AJxx AKxx Qxxx x)
4. 4! (AJxx AKxx AQxx x)

After the strong shortness showing bids, opener picks a suit or rebids in NT with the short suit well-stopped (and hence wasted values for a suit slam).  Over suit agreement, 4NT is RKC. Over 3NT, 4NT by responder is natural and invitational.

When playing a direct 2NT to 1NT as artificial, one must start with 2 Stayman to invite game in NT.

1. Opener with both hearts and spades bids 2
2. The sequence 1NT-2-2-2 shows exactly 4 spades and is invitational to game. Opener may pass, bid 2NT, 3NT, or 4
3. The sequence 1NT-2-2-2N! is invitational to game and denies 4 spades
4. Other sequences that start 1NT-2-2any-2N! do not promise or deny a 4 card major. This should be explained at the time of the 2NT rebid.

3 level responses to 1NT

The OKB 2/1 CC does not specify what the 3 level responses to 1NT should mean. When playing the above gadgets it is right to assume that the sequences 1NT-3 and 1NT-3 are natural non-forcing NT game invites showing 6+ cards with 2 of the top 3 honors and very little on the side (not AKxxxx since opener can duck one round and usually run another 5 tricks; with this holding bid 2NT or 3NT).

The 3 level major suit bids should be avoided without discussion.

When responder is an unpassed hand and rebids the 4th suit in an uncontested auction, it is game forcing and artificial.(eg. 1-P-1-P-1-P-2!-?). Responder is using the 4th suit to indicate a good hand with 12+ points and no attractive rebid. Opener should respond with a natural bid that further describes his hand. Taking the above bidding sequence as an example, opener should rebid as follows:

Opener's Rebid	Shows
2-	Rebid of own 1st/2nd suit at cheapest level, natural, waiting, does not deny extra values
2	Raise partner's 1st suit with 3-card support (Jump raise with more than minimum)
2NT	Bid NT to show stop in the 4th suit and 12-14 or 18-19 points (bid 3N with 15-17 poss unbalanced)
3	Raise 4th suit with 4+ of them
3	Jump rebid of opening suit showing extra length and strength

4SF does not apply in the following situations:

1. In an "up the line" bidding sequence, e.g., 1--1-1. This is not artificial and forcing only for 1 round.
2. When responder's rebid is a jump bid in the 4th suit showing invitational values and at least 5/5 in his bid suits, e.g., 1-1-2-3
3. In competition

With a solid minor of 7 or more cards, open 3NT! (The hand should have no outside Ace or King). If responder has stops in the other 3 suits and no minor void (and no slam interest), he can pass. If he does not have the required stops and entry, he must bid 4 which opener can adjust to 4 if necessary.

Note: The official OKbridge 2/1 summary states that the 3NT bidder should not have a void or small singleton. However, there are almost no hands that meet the requirement and few players who practice it.

Negative Doubles (also known as Sputnik) ( ! )

A negative double shows competitive or better values with no clear bid after partner has opened 1 of a suit and RHO has overcalled in a suit. The double shows about 6+ hcp at the 1-level and about 2 more hcp for each higher level. In OKbridge 2/1, the negative double applies when the overcall is 3 or lower.

The most frequent use of the double is to show a 4 card holding in one or more unbid major suits at any level. However, a negative double also is correct with 5 or more cards in a major when the hand is not strong enough to bid the suit directly. For instance, a new suit at the 2 level shows about 11+ hcp, and at the 3 level or higher is game forcing.

Pard 1	Opp 1	Pard 2	Pard 2 Shows
1	1	X!	6+HCP and 4x . A bid of 1 promises 5
1	1	X!	6+ support points and 4x or 5-10 Points + 5x
1	1	X!	6+ support points and 4/4+ in the majors
1	1	X!	4/4+ in the minors

Note:

1. A direct double of opponent's 1NT opener is penalty oriented.

2. On OKbridge, always include a brief message to the opps when making a negative double: e.g., "=negx" or "=neg". Negative doubles are not alertable in ACBL competition, but are in most other areas.

Note 1: All rebids by the Neg Xer below game are non-forcing, except a cuebid of opps suit.
Note 2: Using Neg Xes means that partner is unable to double for penalty. Therefore, when an opp's suit overcall is followed by 2 passes, opener should try to re-open with a double, if he has 2 or less cards in the opp's suit, since partner may have passed with a good hand for penalties.

Responsive Double ( ! )

The responsive double is a response to partner's takeout double after the opponents have bid and raised a suit. For example: 1 - X - 2 - X! The responsive double is based on the principle that a penalty double is usually unrewarding, therefore the responsive double shows scattered values with at least 6 points and interest in locating a fit. If the opponents are bidding a minor suit, a responsive double asks partner to pick a major suit. If the opponents are bidding a major suit, a responsive double requests partner to choose a minor suit. For instance, advancer might hold KT43 QJ32 93 JT9 and hear: 1 - X - 2 - ?, he should make a responsive double to ask partner to bid a major.

Note: A double by advancer is responsive only when the opponents have opened a one-bid and raised it. Some players also use the responsive double when partner has made a simple overcall in a suit. In this case the responsive double would show 8+HCP, little support for partner's suit, and usually 5/5 or better in the 2 unbid suits: e.g., 1-1-2-X! would suggest 5/5 hearts/diamonds: partner with 3 card or better support for either should bid that suit rather than repeat his own if it is only a 5 carder. With no support for either he will rebid his own suit.

The above description is fine if you have such "perfect" hand types. In practice, however, many players make a responsive double with any hand that has competitive or better values and no other good bid. For example:

1. You hold Kxx KQx xxx Axx and you hear 1-X-2, you have no good call so must use the responsive double and await partner.
2. You hold Kx Axx xxxx Jxxx and you hear 1-X-2, again, you have no good call so must use the responsive double.
3. You hold Txxx KQx xxx Jxx and you hear 1-X-3. Here again, with no good call, you must use the responsive double

A good rule of thumb is not to use an ambiguous bid or sequence when there is a clear specific bid or sequence available

Bidding situations in which double is NOT responsive but for penalty:

1. RHO has bid a new suit, e.g.,1 - X - 1 - X
2. Partner has made a jump overcall, e.g., 1 - 2 - 3 - X
3. LHO has opened with a preempt, e.g., 2 - X - 3 - X
4. Partner has overcalled in no-trumps, e.g., 1 - 1NT - 2 - X

Note: On the OKb 2/1 cc, responsive doubles are on through 3.

Support Doubles and Redoubles ( ! )

You open 1 and hear LHO pass. Partner responds 1 (promising a four-card suit), and RHO butts in with 2. Now what? Users of the support double are happy in this situation; they simply double! to show a three-card spade raise. This lets them bid 2 to show a four-card raise. When the opponents bid and raise a suit, support doubles are also on: they also apply when RHO makes a takeout double

Opener	Opp1	Responder	Opp2	Opener's Rebid Shows
1	1	1	2	Opening values and 3xspades
X!	-?-
1	1	1	2	Opening values and 4xspades
2	-?-
1	Pass	1	X	Opening values and 3xspades
XX!	-?-
1	Pass	1	X	Opening values and 4xspades
2	-?-

Note: On the OKb 2/1 cc, support doubles and redoubles are on through 2

Jacoby 2NT (J2N) ( ! )

If responder jumps to 2NT over a 1/1 opener, it is J2N asking opener to show a singleton or void. It shows 13+ support points, 4+ in opener's suit and is game forcing. Opener rebids as follows:

Opener	Responder	Opener	Opener Shows	Responder
1	2NT!	3!	Max hand, 18+Points and strong suit but denies short suit	Either sign off in game or look for slam
		3/3/3!	Singleton or void in bid suit
		3NT!	Medium hand, 15-17 Points, denies short suit (artificial)
		4	Minimum hand and denies short suit
		4/4/4	Strong 5-card side suit

Splinter Bids ( ! )

The use of an unusual jump bid to show a singleton or void in the suit bid and excellent trump support for partner's last bid suit. This is forcing to game and unlimited.

North	South	Shows
1	3!	13+ support points, agrees hearts, singleton or void spade (forcing).
1/1	4/4!	As above but with club/diamond void/singleton
1	4!	As above but with heart void/singleton

Note:

1. In competition after opponent's t/oX, splinter bids are still "on"
2. In non-competitive auctions, splinter bids may be extended to areas of rebidding, by both opener and responder. In this respect the "rule of thumb" is if a particular new-suit bid would be forcing, then one level higher in that same suit is a splinter bid.
3. Some partners do not like splinters with a singleton A or K.
4. Some partners do not like splinters with a void.
5. Some partners use 1-4 as a splinter. This might seem to be unnecessary when 1-2 is game forcing, thus leaving 1-3 as the unusual jump.
6. A splinter usually cannot be used to show shortness in partner's first bid suit.

2nd Negative - Response over Strong 2 Club Opener

After a negative 2 ("may be waiting") response to a strong 2 opener, it is necessary to expand on those auctions where opener rebids in a suit, since responder is required to bid again even with a bust. To solve his dilemma, the 2nd negative is used: i.e., the cheapest 3 of a minor rebid (if available or 3NT if not), is the 2nd negative: this bid is artificial and shows about 0-4 HCP, but never an Ace. The main advantage of the 2nd negative is obtained when it is not used, making any other rebid by responder constructive, showing useful values. (note: see errors in the OKb 2/1 CC which says 2nd neg is "cheapest 3 level")

Jordan 2NT (Truscott 2NT) ( ! )

1. Over 1 of a Major opening

When opener's 1 of a major opener is doubled for takeout, 2NT! by responder is used to indicate a "limit or better raise" of opener's suit, approx 9-12 points and 4/(3 gd) trumps, forcing to at least 3 of opener's major; this leaves a "jump raise" as preemptive showing 0-8 points (possibly 6-8 if vul) with 4+ trumps, e.g., 1-X-3

After the 2NT! call, opener may

1. signoff in 3 or 4 of his major
2. bid a new suit to try for game or slam., e.g., 1-X-2NT!-3 would be a game try and forcing.

Note: To show a forcing major raise you can use a Splinter bid.

2. Over 1 of a Minor opening

Jordan can also be used when 1 of a minor suit is doubled for takeout, but since it would not be desirable to use 2NT artificially because of of the danger of reaching 3NT from the wrong side, the following 3 agreements are recommended:

1. 2NT is natural and shows approx. 9-11HCP with at least 4 of the bid minor (more usually 5 or 6). It denies a 4-card or longer major and is invitational to game (3N being a possibility since responder is guaranteeing the minor fit) but not forcing
2. 3NT is similar to 2NT but shows approx. 12-14HCP
3. Jump raise showing approx, 6-9 points, at least 5 of the bid minor (or 4 good), and is not forcing, but preemptive

Note 1: If using INVM, a single minor raise would be forcing, even after opp's takeout double
Note 2: A new suit at the 1 level is the same as if the takeout double had not occurred and would be unlimited and forcing for one round by an unpassed hand. This applies only at the 1 level, a new suit at the 2 level is not forcing over opp's takeout double.

A redouble shows 10+HCP, denies a good fit with opener, usually shows 2 other good suits of 4 or more cards and indicates a defence oriented hand, creating a forcing auction. ie., your side must either outbid or penalty double the opps. For example:

Opener	Opp1	Responder	Shows
1	X	XX	10+HCP, less than 3 hearts, decent holding in at least 2 of the other suits, preference for penalising opps. With 3 hearts, a redouble followed by a later heart raise is preferable to a 2NT call With 10+ points, 3 hearts and a good 5+ lower ranking suit, a redouble is necessary, since a 2 level bid is not forcing

Inverted Minors ( ! )

A single minor raise is forcing and a jump minor raise is weak, thus "inverting" the standard meaning of the two bids. When responder has a weak minor raise (eg. 1-2) he is unlikely to "buy" the contract so he may as well bid 3. Conversely if responder has a good minor raise, he wants to keep the bidding as low as possible to allow careful exploration for game, or slam. No hand is too strong for a single minor raise. A classic "rule of thumb" is not to make a weak jump response to an opening bid with more than a poor 6 hcp. This avoids missing game when opener has a balanced 18-19 HCP. For example:

Responses over an Opening of 1 of a Minor

North	South	Shows
1	1NT	6-10HCP balanced hand.Denies 4-card major. Does not deny 4 of bid minor (NF)
1	1NT	6-10HCP, can be very unbalanced when holding long clubs.Denies 4-card major (NF)
1/1	2/2!	Min 10 Points (no upper limit) and 4+trumps, denies 4-card major (forcing)
1/1	3/3!	approx 0-7 support points with 5 or 4 good trumps

After the single minor raise, opener must bid again, (except if responder is a passed hand, or if opener's RHO intervenes with a bid or a double).

Opener's Possible Rebids

North	South	North	Shows
1/1	2/2!	2NT!	Min response suggests NT as final contract
		3/3!	Min response hand unsuitable for NT
		2/2!	4+ of the bid minor, stop in the bid major, says nothing about length of the major
		3NT!	18-19HCP (if playing 15-17NT), balanced hand

After a single minor raise responder is compelled to bid again only if opener rebids in a new suit. Otherwise, responder has the option of passing if he feels the proper contract has been reached.

Responder's Possible Rebids

North	South	South's Rebid Shows
1/1	2/2!	Natural showing 2 raise as minimum
2/2!	2NT!
1/1	2/2!	Minimum single raise (unsuitable for NT)
2/2!	3/3!
1/1	2/2!	Strength in the other minor: may help to enable 3NT
3/3!	3/3!
1/1	2/2!	3 good hearts/spades (South denied 4 with the single minor raise)
2/2!	3/3!
1/1	2/2!	Stops in the 2 unbid suits
2/2!	3NT!

After responder's rebid, any further bidding is governed by the following principle: "After a single minor raise, if either partner returns to 3 or 4 of the agreed minor or 2NT, this is not forcing (except if either partner has bid 3NT prior to a return to 4 of the minor) and indicates minimum values for his previous bidding. Hence, any other bid that does not complete game is forcing.". In competition, the forcing single minor raise is "off" after a single suit overcall (see OKb 2-1 CC errors) or t/oX although it is usual to preempt with a weak hand and trump support over any 1 of a suit opener after a t/oX, e.g., 1--- - X - 3--- indicates v weak hand with 4+trumps

Lebensohl ( ! ) (leb)

A method of contending with the opposition suit overcall of partner's 1NT opening bid. Essentially it involves an artificial response of 2NT. which demands that opener bids 3! as a "relay" bid. Responder may then pass (with clubs) or sign off in his real suit. After a 2-level overcall by the opponents, a response of 3 of a new suit is natural and forcing, e.g., 1NT-(2)-3! (This also applies if it is a jump bid over opp's 2-level overcall: e.g. 1NT-(2)-3!).

If responder, after the Lebensohl 2NT bid, bids a suit that is higher ranking than overcaller's suit, it is invitational to game e.g., 1NT-(2)-2NT!-(P)-3!-(P)-3!). The logic behind this is that if the responder had wished to sign off, he could have bid two immediately after the overcall, which would be weak, just as in standard bidding (e.g., 1NT-(2)-2).

A common problem after an overcall of the 1NT opening is determining whether a stopper is held in the opponent's suit. 3NT is often reached with each partner hoping the other has a stopper, but in fact neither has. This problem can be solved through another application of the Lebensohl convention. Here's how (assume West passes):

e.g.	North	East	South	South's Rebid Shows
A	1NT	2	2NT!	Confirms a heart stop - partner should pass
	3!	Pass	3NT!
B	1NT	2	2NT!	Cuebid is Stayman showing 4 spades and confirms a heart stop
	3!	Pass	3!
C	1NT	2	3NT!	Denies heart stop. Partner must have a heart stop to Pass
D	1NT	2	3!	Denies heart stop but shows 4 spades. Partner must have a heart stop to bid 3NT

Memory Aid: "DD" = "Direct Denies"

After a 2-suited overcall (eg. when opps are using conventions such as Brozel, Astro and Landy) and the overcall is artificial, it is still possible to employ Lebensohl, but with certain modifications as follows:

1. After a 2-suited artificial overcall of 1NT opening, the suit bid is still an "unbid" suit.
2. The agreements re the stop in opp's suit (see above) are "off"
3. After a 2-level artificial overcall, a double is for penalty but the doubler does not promise specific values in the artifical suit but defensive strength (approx 7+HCP) and usually suggests length in one or both of the opp's suits.

Note : After a natural 3-level suit overcall a double is for takeout

A further application of the Lebensohl convention is used after partner has made a takeout double of opponent's weak 2-bid opener. A response of 2NT! (if you are weak and have a long suit) requires the doubler to bid 3! (unless he is v strong and can pass or bid 3NT), then you may pass (with clubs) or sign off in your suit.

East	South	West	North	North's Rebid Shows
2	X	Pass	2NT!	Less than 7HCP with 5+cards in the bid suit
Pass	3! (relay)		Pass (with clubs)/3

Note 1: The failure to engage the Lebensohl 2NT bid gives a constructive/forcing meaning to 3-level suit responses to partner's takeout double
Note 2: If the suit bid at the 3 level, after engaging the Leb 2NT is a higher ranking suit than the opp suit, then it is invitational, e.g., 2-X-2N!-3!-P-3!.

New Minor Forcing (NMF) ( ! )

The use of a bid in an unbid minor suit by responder as an artificial convenient forcing bid after a 1NT rebid by the opening bidder. Much like "4th Suit Forcing (4sf)". It promises about 11+HCP and is most frequently used when responder has a 5-card major suit as a means of enquiring about 3-card support. With a choice of "new minor" bid the longer and stronger to suggest a stopper.

NMF is also effective when responder has 5/4 spades/hearts (after a minor-suit opening). It asks opener for a 4-card heart suit, as well as for 3-card Spade support.

NMF may also be used as a temporising bid when responder wishes to invite game in his own suit, or in opener's suit. This is the only means of describing such hands of invitational strength, assuming that responder's 2nd-round jump bids are forcing.

After the NMF forcing bid, opener must further describe his distribution, in order to help responder locate the best contract. In most cases, opener may also indicate whether he holds minimum or maximum strength for his 1NT rebid.

Note: In competition if either opponent has bid, the NMF convention is "off": responder's rebid in a new minor after opener's 1NT shows a real suit and is not forcing.

3rd Round Bids Available to Opener

Priority	Opener	Responder	Opener's 3rd Rnd call Shows
1	1	1	Shows 4 hearts by bidding the unbid major. Does not deny 3xspades
	1NT	2!
	2!	?
2	1	1	Show 3 hearts and min/max 1NT rebid
	1NT	2!
	2/3!	?
3	1	1	Denies 3 spades, shows club stop and min/max 1NT rebid
	1NT	2!
	2NT/3NT!	?
4	1	1	Denies 3 spades, no diamond stop and min 1NT rebid
	1NT	2!
	2!	?
5	1	1	Denies 3 hearts, no spade stop, does not agree clubs but shows 4 of them
	1NT	2!
	3!	?

Responder's 3rd Round Available Bids
Pass	If opener's 3rd round bid is the logical contract
Any Minimum Bid	Natural (agreeing suit/NT) (if below game invitational)
Any Jump Bid	Natural (agreeing suit) (if below game forcing)
After 2 3rd rnd bid by pard (showing 4x), with 5x and less than 4x, bid 2	Asks if pard has 3 spades (forcing for 1 rnd)

If the NMF convention is adopted, responder must know the proper methods of describing 2-suited hands (at least 5/5 shape) after opener's 1NT rebid:

1. With a weak 2-suiter, responder may (a) rebid a reasonably good 5-card major or (b) pass. Do not bid a new minor suit. (With 5/5 majors, responder is able to bid both suits).

2. With an invitational 2-suiter, responder should bid a new minor, even when holding both majors. Then on the next round, responder may bid his 2nd suit (unless opener's 3rd bid has indicated an obvious final contract).

3. With a game-forcing 2-suiter, responder should jump in his 2nd suit.

Reverse Drury (rdrury) ( ! )

An improved version of Drury that "reverses" the meanings of opener's rebids. RDrury is an effective way to gauge the strength of partner's 3rd/(by arrangement,4th seat) 1 of a major opener. 2! by responder shows 10-12 points with at least 3 card support for the bid suit. Drury, and all its variations, is off if the 1 of a major is doubled/overcalled (with discussion it can be "on")

Opener	Responder	Opener	Shows
1-	2!	2!	Artificial, showing full opening hand (with 3/4+ majors, responder should bid 2/ to cater to opener having 5/4 majors)
		2-!	Rebid of suit=subminimum hand, responder should pass
1	2!	2!	At least 5/4 spades/hearts, denies opening strength. Responder can pass with 4 hearts or return opener to spades
1	2!	3-!	Good 5 card minor. Does promise opening strength, since the pship is committed to the 3-level. (forcing)

Note: If responder really wants to show a long good minor he needs to bid 3/ over 1/

Defence to Strong 1 and 2 Club Openers

Over strong 1 or 2 Openers by Opps, Double asks partner to bid his better major and 1/2NT asks for his better minor (Unusual NT)

Cappelletti! (Capp) (also known as Hamilton or Ham) ( ! )

Used versus opponent's opening of 1NT in direct and balancing positions.

The Overcalls of 1NT are:

East	South	Shows
1NT	X!	Strong hand (penalty oriented)
	2!	1-suited hand Respond with 2! (Pass only if you have a good 6-card club suit). Partner can pass with diamonds or correct to his suit
	2!	At least 5/4 in the majors
	2!	hearts + a minor
	2!	spades + a minor
	2NT!	Both minors

Possible responses to Cappelletti:

Capp O/Call	North	Shows
X! Strong Penalty	Pass	Can stand the X
	2 x Suit	Weak takeout, can't stand the X
2 ! 1-Suited	2!	Relay asks Pd. to bid his suit – Pd will pass if suit is diamonds or correct.If Pd has 6x+4x, he can show this by bidding 2NT! over the 2! relay
	Pass	Poor hand with long decent clubs
	2-!	Good 5+-card major
	2NT!	11-13HCP balanced hand (invitational)
2! 5/4+Majors	Pass	Poor major suit support with long good diamonds
	2-	Minimum response - major suit preference (NF)
	3!	Poor major suit support with long good clubs
	2NT! (force 1rnd)	Either a minor-suit hand or limit raise in 1 of the majors (if the latter the plan is to rebid 3- after pd has shown his better minor) (NF,invitational)
	3-!	Preemptive in accordance with "The Law of Total Tricks"*
2! hearts+minor (NF)	Pass	Content to play in 2
	3!	Preemptive as * above
	2NT! (force 1rnd)	Asks Pard to bid his minor or shows a limit raise, eg.,1NT-2!-P-2NT!-P-3-All Pass or, 1NT-2!-P-3-3(invitational,NF)**
2! spades+minor (NF)	Pass	Content to play in 2
	3!	Preemptive as * above
	2NT! (force 1rnd)	Asks Pard to bid his minor or shows a limit raise as ** above but spades instead of hearts
2NT! both Minors	3-!	Preferred minor
	3!	A good major suit of your own and 11+HCP (more likely vs wk NT)(NF)
	Pass/3NT!	11+HCP Balanced hand with good major stops (more likely vs wk NT)

Note:

1. The above responses assume Opp2 passes. If Opp2 doubles the 2 overcall, then a redouble shows 7+HCP and support for all suits inviting the Overcaller to compete at the 3-level
2. The Partnership may agree that a double by a passed hand shows a 4-card major + a longer minor, or that a double shows clubs. Neither of these is part of OKbridge 2/1
3. Capp may also be used over openings of 2/3NT (including Gambling 3NT) by partnership agreement (not part of OKbridge 2/1)
4. Further, the Partnership may also agree to use Capp after one partner has opened the bidding with 1/1 and opponent has overcalled 1NT. In this case, Partner2's Capp overcalls at the 2-level would have the same meaning as above and would indicate a weak hand of 8 or less Points, since with a stronger hand he would double for penalty

Roman Key Card Blackwood (RKC)

The answers to RKC include the King of trumps as an extra control card (ie. 5 control cards: 4 Aces and King of trumps). OKbridge 2/1 uses 3014, but many players prefer 1430

RKC 0314/3014 asking for Controls			RKC 1430 asking for Controls
4NT	5	0 or 3 controls	1 or 4 controls
	5	1 or 4 controls	3 or 0 controls
	5	2 or 5 controls without Q Trumps	2 or 5 controls without Q Trumps
	5	2 or 5 controls with Q Trumps	2 or 5 controls with Q Trumps

After the reply to 4NT, 5 of the trump suit is a signoff. If the reply is 5 or 5, the cheapest relay asks for the trump Queen, and the next cheapest relay is used to ask for Kings. If the reply is 5 (denying the trump Queen) or 5 (showing the trump Queen), then the cheapest relay is used to ask for side suit Kings.

Note 1 (with patnership understanding):

1. A 5NT response to 4NT can show an 0 or 2 controls with a working void
2. 6 of any suit below the trump suit can show 1 or 3 controls with void in the bid suit
3. 6 of the agreed trump suit can show 1 or 3 controls with a void in a higher ranking suit

Note 2:

1. A 5NT rebid by the RKC bidder, when it is not a 1st or 2nd relay, asks for the cheapest King. With the club King, for example, responder would bid 6.
2. Many players expect that asking for the trump Queen or for Kings is a grand slam try that guarantees that all keycards are held by the partnership. If so, then either partner is entitled to go to the 7 level when their unshown holdings are judged to be "the right stuff".
3. The relays re Q of trumps and asking re Kings are based on "agreed trump suit" - if no trump suit has been agreed (eg., 1-P-1-P-4NT), you should assume the last bid suit is the trump suit, ie., spades
4. Relays exclude the agreed trump suit which would be used to signoff.
5. If an Ace/Control is missing be aware that to ask about Kings may take you over 6 of the agreed suit.
6. Some players show Zero Kings by bidding 6 of the agreed suit and specific Kings by bidding the cheapest suit in which a King is held. Some players bid 5NT to show a King in a suit above the trump suit. If you are in any doubt as to what any of the replies mean, ask the RKC bidder.

RKC Asking for Side Suit Kings & Q of Trumps

North (RKC ? Aces)	South (RKC ? Aces Reply)	Agreed Trump Suit	North	South	Shows
4NT	5	clubs	5 ? trump Q	5	No trump Q
				5	Trump Q
			5 ? Kings	5	0
				5NT	1
				6	2
				6	3
		diamonds	5 ? trump Q	5	No trump Q
				5NT	Trump Q
			5 ? Kings	5NT	0
				6	1
				6	2
				6	3
		hearts	5 ? trump Q	5	No trump Q
				5	Trump Q
			5 ? Kings	5NT	0
				6	1
				6	2
				6	3
		spades	5 ? trump Q	5	No trump Q
				5	Trump Q
			5 ? Kings	5	0
				5NT	1
				6	2
				6	3
4NT	5	clubs or diamonds	5 ? trump Q	5	No trump Q
				5NT	Trump Q
			5 ? Kings	5NT	0
				6	1
				6	2
				6	3
		hearts	5 ? trump Q	5NT	No trump Q
				6	Trump Q
			5NT ? Kings	6	0
				6	1
				6	2
				6	3
		spades	5 ? trump Q	5	No trump Q
				5NT	Trump Q
			5NT ? Kings	6	0
				6	1
				6	2
				6	3
4NT	5	clubs, diamonds or hearts	5 ? Kings	5NT	0
				6	1
				6	2
				6	3
		spades	5NT ? Kings	6	0
				6	1
				6	2
				6	3
4NT	5	clubs diamonds hearts spades	5NT ? Kings	6	0
				6	1
				6	2
				6	3

OKbridge 2/1 CC

OKbridge 2/1 CC
System	Simple 2/1 GF Always by unpassed hand, except in comp
NT	15-17,Jxf,Txf*,Leb,sys on over x,2S=mss or correct to 3d with diam bust, 2N->3C cl signoff or bid stiff in 4-4-4-1 next
2NT	20-21,Jxf,Txf*,3S=MSS,sys on /x 3N=gmblg no outside A or K
3NT	3N=gmblg no outside A or K
Majors	5cm, J2N(4X=2nd suit),1N=1 rd frce,rev drury,pjs in comp, 3N=balanced 16-17 HCP (4-3-3-3 or 4-4-3-2)
Minors	3+(usually 4 diam), inverted (off in comp*) (force to 2nt or 3min),2N=11-12,3N=13-15,bypass 1D unless GF strength
Strong	2C - 2D wait, cheapest 3 minor(3N over 3D rebid) is 2nd neg*
Weak	5-11(wider 3rd, stronger 4th),2NT-feature,RONF
Overcalls	8-16,new suit nf tends to deny good supp, Q=1rd frce, Q then new suit forcing, weak raises if next opp doubles
NT-Over	System on-incl Lebenshol* if next opp bids
Doubles	Neg-3S, Resp-3S, Support x and xx ->2H
Vs.Doubles	Jordan 2N (maj and min), raises are weak if partner opener-new frce 1 level only,xx implies no fit 10+
Preempts	standard type (gen rule of 2 and 3), new suit forcing
Vs.Preempts	X=takeout, Lebenshol/weak 2 all seats
Cuebids	Michaels over maj or min (2N asks minor), nat over artificial
Slam-Bids	0314 RKC(last bid suit unless only 1 fit established)
Suit-leads	4th best, Xxx, Akx(x)A(i.e, lead A from 3 or more to the AKQ)
NT-leads	4th best,Xxx,A asks honor-count if none, K asks attitude
Carding	standard signals
Misc	4SF(GF), NMF, capp/nt, over strong 1C or 2C X=maj, NT=minors

* = Corrections to OKb 2-1 CC

1. INVM "off in comp", the OKb 2-1 CC says "off /x"
2. "Leb over 1NT" not over 2NT as stated in the 2-1 CC
3. /Strong 2C, 2C - 2D wait, cheapest 3 minor(3N over 3D rebid) is 2nd neg whereas the OKb 2/1 CC, states "cheapest 3 level".
4. Texas Transfers are "on" in competition through 3. (OKb 2/1 CC says "on /x" but recommends that they are "on" in the OKb 2/1 notes)

See also Common Practice Conventions which most players use but are not listed in the OKb 2-1 CC