Слабый взнос в бридже: варианты и история применения.

Common treatment used in the game of contract bridge
The weak two bid is a common used in the game of contract bridge, where an opening bid of two diamonds, hearts or spades signifies a weak hand, typically containing a long suit. It may be deployed within any system structure that offers a forcing artificial opening to handle hands of (eg) 20+ points, or an expectation of 8 or more tricks. It is form of preemptive bid. The strong call releases any remaining two level openings for pre empting your opponents. In North America it is commonly used in combination with the strong two clubs convention. Worldwide there are many other variants, the commonest being a strong one club. “Weak Two” refers specifically to an opening bid, not to be confused with the "weak jump overcall". That denotes a similar hand type, made over an opponent's opening bid.

2S is most powerful in terms of pre emption against your opponents. 2H is less so, easily defended by either a take out double or a 2S overcall. Paradoxically the 2D opening can be very disruptive. Your opponents have to explore potential fit in both majors, and then play at the correct level. 2C pre emption is uncommon, almost always associated with forcing 1 level agreements.

A prototype of the weak two was used in auction bridge, and the principle was attested as early as 1910 by J. B. Elwell. It was incorporated into the Vanderbilt Club system. In early 1940s, Howard Schenken developed the modern weak two bid along lines similar to Vanderbilt's. In Charles Goren's original bidding system, when a player opened the bidding with two of a suit, this signified that the player held a very strong hand. (This later became known as the strong two bid.) Later players found it more effective to reserve only the conventional two clubs opening, to show a strong hand. That left the room for opening bids of 2D, 2H, or 2S to show a weak hand with a six card suit. This became known as the weak two bid. In some systems, a bid of 2C shows a strong hand with a five card suit, and a bid of 2D shows a hand that is similarly strong, but balanced. These alternate versions are less common.

Playing Parallel Twos an opening 2C shows five hearts 7 11 HCP, 2D shows five spades 7 11 HCP. The 2C and 2D opener's are referred to as Parallel Twos because they are played in parallel with the regular six card weak twos in hearts and spades. You can play them in any bidding system Acol, SAYC, Precision, Blue Club etc. See the eBook "Parallel Twos For You" N. Jones June 2014.

The European Muiderberg convention, (co invented by Alan Woo of London) allows weak two level bids to be made on 5 card suits with a 4+ lower ranking side suit. They have equal pre emption and are more common than the 6 card, or 5 5 hand types. Typically a non vulnerable Muiderberg Two shows 5 9 points, 2NT is often used as strong enquiry, with 3C asking opener to pass or correct to 3D). This style melds well with a multi 2 diamonds so that regular 6 card hand types may also be expressed. Lucas twos are even more flexible. You open the five card suit. The four card suit may be higher, or lower.

An opening showing either 5+4+ or 4+4+ cards in two specified suits. Superficially reckless, the hand type is extremely common, around 2½ times more so than the 6+ type. risk is to be taken for a penalty. Against that you’re probability of finding eight card or better fit is 68%, and 65% respectively. The law of total tricked protects you at two level as if a significant penalty is available, opponents will often do better bidding game in their own fit denomination.

Playing Parallel Twos an opening 2C shows five hearts 7 11 HCP, 2D shows five spades 7 11 HCP. The 2C and 2D opener's are referred to as Parallel Twos because they are played in parallel with the regular six card weak twos in hearts and spades. You can play them in any bidding system Acol, SAYC, Precision, Blue Club etc. See the eBook "Parallel Twos For You" N. Jones June 2014.

Antispades Twos (also known as Antispades Weak Twos) make up a two level opening based on either a six card suit or a two suiter with at least nine cards distributed across any two suits. The 2C opening promises 5 10 HCP and either a 6 card club suit, or clubs and diamonds, or clubs and spades. The 2D opening promises 5 10 HCP and either a 6 card diamond suit, or diamonds and hearts, or diamonds and spades. The 2H opening promises 5 10 HCP and either a 6 card heart suit, or hearts and spades, or hearts and clubs. (The 2S opening is artificial and very strong, promising either 23+ HCP balanced, or a hand of 16+ HCP with four losers or fewer.) Partnerships can adopt Weak, Parallel, Lucas or Antispades Twos and retain their existing one level bidding structure — for example, Acol or Five card Majors — along with a strong balanced meaning for the 2NT opening.