Variations on the basic themes

Bidding systems depart from these basic ideas in varying degrees. Standard American, for instance, is a collection of conventions designed to bolster the accuracy and power of these basic ideas, while Precision Club is a system that uses the 1 opening bid for all or almost all strong hands (but sets the threshold for "strong" rather lower than most other systems usually 16 high card points) and may include other artificial calls to handle other situations (but it may contain natural calls as well). Many experts today use a system called 2/1 game forcing (enunciated as two over one game forcing), which amongst other features adds some complexity to the treatment of the one notrump response as used in Standard American. In the UK, Acol is the most common system; its main features are a weak one notrump opening with 12-14 high card points and several variations for 2-level openings. There are also a variety of advanced techniques used for hand evaluation. The most basic is the Milton Work point count, (the 4-3-2-1 system detailed above) but this is sometimes modified in various ways, or either augmented or replaced by other approaches such as losing trick count, honor point count, law of total tricks, or Zar Points. Common conventions and variations within natural systems include: Point count required for 1 NT opening bid ('mini' 10-12, 'weak' 12-14, 'strong' 15-17 or 16-18) Whether an opening bid of 1 and 1 requires a minimum of 4 or 5 cards in the suit (4 or 5 card majors) Whether 1 (and sometimes 1) is 'natural' or 'suspect' (also called 'phoney' or 'short'), signifying an opening hand lacking a otable heart or spade suit Whether opening bids at the two level are 'strong' (20+ points) or 'weak' (i.e., pre-emptive with a 6 card suit). (Note: an opening bid of 2 is usually played in otherwise natural systems as conventional, signifying any exceptionally strong hand) Blackwood (either the original version or Roman Key Card) Stayman (together with Blackwood, described as "the two most famous conventions in Bridge".[28]) Whether the partnership will play Jacoby transfers (bids of 2 and 2 over 1NT or 3 and 3 over 2NT respectively require the 1NT or 2NT bidder to rebid 2 and 2 or 3 and 3), minor suit transfers (bids of 2 and either 2NT or 3 over 1NT respectively require the 1NT bidder to bid 3 and 3) and Texas transfers (bids of 4 and 4 respectively require the 1NT, or 2NT bidder to rebid 4 and 4) What types of cue bids (e.g. rebidding the opponent's suit) the partnership will play, if any. Whether doubling a contract at the 1, 2 and sometimes higher levels signifies a belief that the opponents' contract will fail and a desire to raise the stakes (a penalty double), or an indication of strength but no biddable suit coupled with a request that partner bid something (a takeout double). Whether doubling or overcalling over opponents 1NT is natural or conventional. Most common artificial agreement is Cappelletti, where 2 is a transfer to be passed or corrected to a major, 2 means both majors and a major shows that suit plus a minor. How the partnership's bidding practices will be varied if their opponents intervene or compete. Which (if any) bids are forcing and require a response.