| 词条 | OKbridge 2/1 |
| 释义 |
}} OKbridge 2/1 is a duplicate bridge bidding system combining two-over-one game-forcing and Walsh bidding methods. Popular with internet bridge players on the OKbridge website,[1] this style of 2/1 bidding results from the combination of five bidding conventions and principles. Each takes on a slightly different meaning from those in other bidding systems, but the combination results in a superior description of a hand's high card strength and shape. These principles and conventions are:
This system is consistently based on the principle of slow arrival: the stronger the hand, the slower the bidding sequence progresses. Conversely, all jumps will tend to deny strength or act in a preemptive manner to use up bidding space and deny the opponents the opportunity to describe their hands. Unlike most hand evaluation methods, OKbridge 2/1 describe shape and strength separately, i.e. distributional points are not added to high card points. Five-card majorsThis is almost the same as the Five-card majors bidding system used in SAYC. To review, a player must have five cards in hearts or spades to open (along with 12 high card points; the fifth major card is considered to be the 13th point). This often makes it necessary to open the bidding with “one club” in the case of a four-card major even if opener does not have clubs with which to play. Responder of course knows that the “one club” opening bid may or may not suggest clubs as the trump suit, as the priority in duplicate bridge is to find an eight card or longer fit in a major suit (the golden fit), or perhaps a game in notrump. Each partner understands that subsequence bidding sequences will clarify its true meaning. The Walsh bidding method detailed below will have some impact on the five-card major concept. Unlike SAYC, partners with interest in the majors (four cards in one or both major suits) should always open the bidding with “one club” regardless of the length and strength of the clubs or diamonds in their hand. The opening bid of “one diamond” alternatively denies interest in a major suit. Rule: only open hearts and spades with five in the suit. With a four-card major, always open “one club." Bids following the opening bid will clarify if the opening bid suggests clubs as a trump suit or interest in a major. Bids opening “one diamond” are reserved for a good diamond suit with an unbalanced hand and without a four-card major. The “two over one” game forceThis is basically the same as the typical 2/1 game forcing convention, showing game strength but also implies a balanced or semi-balanced hand. It is one of the options in responding to openers 5-card major including:
Examples of a 2/1 response: 1{{Hearts}} - 2{{Clubs}}; 1{{Hearts}} - 2{{Diamonds}}; 1{{Spades}} - 2{{Clubs}}; 1{{Spades}} - 2{{Diamonds}}; and 1{{Spades}} - 2{{Hearts}}. The 2/1 bid shows both game strength (perhaps with slam interest) and also conveys additional information about responder’s hand. Of course, the 2/1 response should never be passed by the opening partner because the next bid by responder will clarify if the responder has support for partners 5-card major. Rule: Over a 5-card major, a 2/1 bid by an unpassed hand is forcing to game. The value of the 2/1 game forcing bid is that with the slow arrival concept and early game force, there is a lot of opportunity in the remaining bidding space for both partners to describe their hands and explore for a potential slam. With this opportunity we can find additional slams based on combined points and shape, instead of just on high card points alone. Additional bidding conventions will make this all worthwhile. WalshThe Walsh style of bidding stands in opposition to the concept of bidding up the line. With the OK Bridge 2/1 bidding system, use Walsh to show a 4-card major and sufficient high card points to force to game. The Walsh convention is a “one diamond” response to an opening bid of “one club.” The convention is invoked by responder with interest in a major suit game. If responder has a 4 card major without sufficient strength for game, then responder bids that suit up the line (i.e. skips the “one diamond” bid to deny game forcing strength). The bidding sequence is:
In SAYC, a balanced hand has no voids, no singletons, and at most one doubleton; non-balanced hands include all others. In OK Bridge 2/1, a balanced hand is without voids or singletons: a non-balanced hand has one or more voids or singletons whereas hands with one or more doubletons are considered semi-balanced. Hands with voids or singletons add strength to declarer’s situation, and the ability to show this strength clearly (yet separately from high card points) is of considerable value. For example, in the sequence 1C-1D-1NT, the openers jump to 1NT is showing a balanced hand or semi-balanced hand with 12-14 points (i.e. no voids or singletons). Alternatively, the sequence 1C-1D-1H usually shows 4 hearts with a side singleton or void, and 1C-1D-1S usually shows 4 spades with a side singleton or void and denies 4 hearts. (It shows extra strength and denies a balanced minimum opening hand. These bids are also used with 16 points or more and semi-balanced hands, in which case it is undesirable to show a balanced minimum 1NT, and you also could not open 1NT.) When responder skips the Walsh “one diamond” response and bids a four-card major, this shows a weak unbalanced hand (usually 6-9 points). If the opener responds to the 1{{diams}} Walsh bid by skipping over the major suits and replies 1NT, then this shows a balanced or semi-balanced hand without additional strength by voids and singletons. With the principle of “slow arrival,” notice how skipping some bids denies some additional strength. Rule: When partner opens “one club,” respond “one diamond” if you have a four-card major and game interest. Forcing NotrumpThe forcing notrump convention is needed to complete the 2/1 game forcing convention: unlike in SAYC, a bid of one notrump (1NT) by an unpassed hand in response to a five-card major opening does not show a weak hand, does not deny support for partners bid, does not deny a four-card major, and is forcing for one round – opener must bid again. The 1NT response to partners five-card major opening is a catch all. It denies a game force and tends to deny an unbalanced hand. The purpose of the forcing 1NT bid is to show a balanced (or semi-balanced) hand without enough strength (6-11 points) to respond with a 2/1 bid. The forcing notrump is for both weak and invitational hands but denies any additional strength from the hand shape (i.e. no “shape points”). The next bid will clarify if weak support is available for partners opening bid. Since the 1NT bid is invoked with both weak and intermediate hands, it is possible for partnerships with two weak hands to get into some trouble. In theory, this is a small price to pay in weak situations relative to the benefits in other situations of showing extra strength from voids and singletons. In practice when the bidding stops at 1NT, the opponents would probably balance the bidding and take over the auction, so very little is given up. Rule: A 1NT bid over a five-card major by an unpassed hand is forcing for one round. To summarize, opener bids as follows (very similar to SAYC):
To summarize responses to partners five-card major opening, options are:
New Minor ForcingThe New minor forcing (NMF) convention is invoked by responder after openers 1NT rebid. In the OK Bridge style of 2/1, NMF is a last resort when responder wants to continue looking for a fit. This means NMF is not used in a 1C – 1D sequence (which is Walsh bidding), is not used when opening a 5-card major (where we use the 2/1 game force) or a no-trump opening (where we use Stayman and other conventions). In OK Bridge 2/1, NMF is used to:
Be careful what other articles you read about NMF: it is a popular convention in several bidding systems but has different use and meaning among the systems. In our system here, NMF is limited and specialized. Since 1 clubs will often be opened in 2/1, responders rebid of “two diamonds” following openers rebid of 1NT invokes NMF. On occasion, opener will start with 1 diamonds and later rebid 1NT, in which case NMF is invoked by responder by rebidding “2 clubs.” As responder, your invocation of NMF tells opener you have a 5-card major and enough points (9 to 12) to at least invite game. Responder's follow-up bid shows whether NMF has been used on an invitational hand or whether responder's hand is forcing to game. The only rebids by responder that are not forcing to game are pass, 2NT, or returning to his major suit at the 2-level. Rounding out the OK-Bridge 2/1 bidding system (i.e. instead of Walsh, 5-card majors, and NT openers), NMF only applies to these six specific bidding sequences:
When responding to partners NMF, it is best to:
Rule: As responder, use NMF over openers rebid of 1NT (non-forcing) to show a 5-card-major. References1. ^Official OKbridge website {{WPCBIndex}}{{DEFAULTSORT:OK bridge 2 1}} 1 : Bridge systems |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。