Editing Contract bridge (section)

====Basic natural systems====
As a rule, a natural suit bid indicates a holding of at least four (or more, depending on the situation and the system) cards in that suit as an opening bid, or a lesser number when supporting partner; a natural NT bid indicates a balanced hand.

Most systems use a count of [[high card point]]s as the basic evaluation of the strength of a hand, refining this by reference to shape and distribution if appropriate. In the most commonly used point count system, aces are counted as 4 points, kings as 3, queens as 2, and jacks as 1 point; therefore, the deck contains 40 points. In addition, the ''distribution'' of the cards in a hand into suits may also contribute to the strength of a hand and be counted as [[Hand evaluation|distribution points]]. A better than average hand, containing 12 or 13 points, is usually considered sufficient to ''open'' the bidding, i.e., to make the first bid in the auction. A combination of two such hands (i.e., 25 or 26 points shared between partners) is often sufficient for a partnership to bid, and generally to make, game in a [[major suit]] or notrump (more are usually needed for a [[minor suit]] game, as the level is higher).

In natural systems, a 1NT opening bid usually reflects a hand that has a relatively balanced shape (usually between two and four (or less often five) cards in each suit) and a sharply limited number of high card points, usually somewhere between 12 and 18&nbsp;– the most common ranges use a span of exactly three points (for example, 12–14, 15–17 or 16–18), but some systems use a four-point range, usually 15–18.

Opening bids of three or higher are preemptive bids, i.e., bids made with weak hands that especially favor a particular suit, opened at a high level in order to define the hand's value quickly and to frustrate the opposition. For example, a hand of {{BridgeHandInline|KQJ9872|7|42|763}} would be a candidate for an opening bid of 3{{Spades}}, designed to make it difficult for the opposing team to bid and find their [[optimum contract]] even if they have the bulk of the points. This hand is nearly valueless unless spades are trumps but it contains good enough spades that the penalty for being set should not be higher than the value of an opponent game. The high card weakness makes it likely that the opponents have enough strength to make game themselves.

Openings at the 2 level are either unusually strong (2NT, natural, and 2{{Clubs}}, artificial) or preemptive, depending on the system. Unusually strong bids communicate an especially high number of points (normally 20 or more) or a high trick-taking potential (normally 8 or more). Also 2{{Diams}} as the strongest (by HCP and by DP+HCP) has become more common, perhaps especially at websites that offer duplicate bridge. Here the 2{{Clubs}} opening is used for either hands with a good 6-card suit or longer (max one losing card) and a total of 18 HCP up to 23 total points – or "{{frac|2|1|2}}NT", like 2NT but with 22–23 HCP. Whilst the 2{{Diams}} opening bid takes care of all hands with 24 points (HCP or with distribution points included) with the only exception of "Gambling 3NT".

Opening bids at the one level are made with hands containing 12–13 points or more and which are not suitable for one of the preceding bids. Using [[Standard American]] with [[Five-card majors|5-card majors]], opening hearts or spades usually promises a 5-card suit. Partnerships who agree to play 5-card majors open a minor suit with 4-card majors and then bid their major suit at the next opportunity. This means that an opening bid of 1{{Clubs}} or 1{{Diamonds}} will sometimes be made with only 3 cards in that suit.

Doubles are sometimes given conventional meanings in otherwise mostly natural systems. A natural, or ''penalty'' double, is one used to try to gain extra points when the defenders are confident of setting (defeating) the contract. The most common example of a conventional double is the [[takeout double]] of a low-level suit bid, implying support for the unbid suits or the unbid major suits and asking partner to choose one of them.