Slam-seeking conventions

From Wikipedia, the free encyclopedia

This article concerns Contract Bridge and uses terminology associated with the game. See Contract bridge glossary for an explanation of unfamiliar words or phrases.

In contract bridge, bidding and making a small slam (12 tricks) or grand slam (13 tricks) presents an attractive proposition, as the bonuses range from 500 to 1500 points. However, in order to bid and make a slam, the partnership should ascertain that the right conditions are met as failure to fulfill the slam contract also means failure to score the bonus points for a game (300-500).

Contract bridge bidding systems are mainly "natural" (i.e. most bids have an obvious meaning) or "artificial" (i.e. many bids have a meaning unrelated to the denomination mentioned). However, even natural systems such as Acol find occasional need to resort to artificial means called conventions. A very common type of conventional bid is of the slam-seeking variety to be used in situations when a small slam or a grand slam appear possible but additional information is needed before the optimum contract can be detirmined.

In order to make a small slam (grand slam) the combined strength and shape of the two hands must be sufficient to take 12 (13) tricks and the opponents must not be able to cash two (one) tricks before declarer has set up those 12 (13) tricks. It is widely considered (for example Klinger 1994 and Root 1998) that 33 high-card points are needed for making a small slam in no trumps, and 37 high card points for a NT grand slam. However, slams in a suit can be made with fewer high-card points if the two hands fit well, e.g. have no "wasted values", have a double fit (8+ cards in both trump suit and a side suit), have "primary values" (aces and kings) rather than "secondary" ones (jacks and queens), or are shapely (with long suits and voids or singltons).

Several bidding methods have been devised to establish whether these conditions can be fulfilled. There are pros and cons with each method and none is suitable for all circumstances. Part of the skill of a good player lies in selecting the method most suitable for conditions at the table.

Methods in common use include:

Blackwood is possibly the earliest slam-seeking convention invented, and one of the most widespread. A bid of 4NT is used to query partner about the aces held (and trump king or even queen, in some variations); the replies are stepwise. A bid of 5NT queries partner about kings. Blackwood is used once the combined strength of the hands has been ascertained and a trump suit has been agreed.

Gerber is similar to Blackwood but the initiating bid is 4C not 4NT. Gerber is used after NT opening bids and rebids (and on other occasions by partnership agreement).

Quantitative no trump bids are not concerned with aces or kings but are used to establish whether two relatively balanced hands have sufficient HCP. They are used only for seeking a slam in no trump, after no trump opening bid or rebid.

Cue bids are used to communicate specific controls (aces or voids ... and, in more advanced forms, kings and singletons). Once a trump suit has been agreed and the two hands are considered to be strong enough, partners bid the lowest available suit which they control; this process continues until one of the partners has sufficient information to make the final bid, either a game or a slam.

Grand slam force uses a direct bid of 5NT to query the quality of partner's trump suit. It cannot be used following Blackwood because the bid of 5NT asks for kings, but it can be used following cue bids or Gerber.

Splinter bids are used early in the bidding to communicate a strong hand, with a fit for partner's last bid suit and a side-suit singleton. This splinter bid is a double jump in the singleton suit. Partner of the splinter bidder will then typically bid game or proceed with cue-bids to investigate the slam further.

Asking bids combine the approaches of Blackwood and cue bids. As in Blackwood, one partner takes over the control and asks the other for his holding, but as in cue bid, it is related to a specific suit. The partner replies stepwise about holding in the queried suit. The original Asking bids, as devised by Charles Goren are nowadays largely superseded by cue-bids, but the approach is still frequent in many artificial systems, such as Precision Club.

Relay bids present a highly artificial codified scheme, where one partner takes full control early in the auction and just bids the cheapest available bids (relays), and the other describes distribution and controls in detail. The scheme based on relays, where one partner describes an absence of controls (rather than presence, as in cue bids), is known as Spiral scan, and can be combined with Blackwood, even in natural systems.