Acol

Origins

Bidding system structure

• It is a natural system: most opening bids, responses and rebids are made with at least four cards in the suit bid, and most no trump bids are made with balanced hands.
• It is a four-card major system: only four-card suits are required to open 1 or 1, unlike Standard American and many other systems where five-card suits are typically required.
• It is an approach forcing system: as in most modern bidding systems, a new suit in response to a suit opening is forcing, unlike some older systems such as Vienna, which require responder to jump in order to force opener to bid again.
• It makes extensive use of limit bids: limit bids describe the hand so closely, in terms of high card points and shape, that the one who makes the limit bid is expected to pass on the next round, unless partner makes a forcing bid.
• Understanding and correct use of limit bids and forcing bids is fundamental to applying the system: all no trump bids below the level of 4NT are limit bids, as are all suit bids that merely repeat a suit already bid by the partnership; changes of suit may be forcing or not depending on the approach bids.
• The level of the 1NT opening bid influences other bids: the normal choice is between a "weak no trump" and a "strong no trump", but normally in Acol a weak NT is used throughout, unlike Standard American which uses a strong NT. In earlier forms of Acol, a "variable no trump" was common; 12–14 non-vulnerable and 16–18 vulnerable.
• It is the only "fully natural" bidding system which does not require a "short club" or "prepared" club or diamond bid with less than four cards. All opening bids at the one-level promise at least four cards in the bid suit.

  Variants

• Acol: unregulated Acol, from the simple to the complex, remains in common use throughout the UK. At any one time the version in most common use will be known as "Standard Acol" although this term will mean different things to different players and is sometimes confused with Standard English Acol.
• Standard English Acol or Bridge for All Acol. Developed by the English Bridge Union in 1996, and designed to facilitate the learning of bridge and to provide standardised guidance to novices, intermediate players and their teachers. This variant uses the weak 1NT opening and strong two opening bids. Simple conventions such as Stayman, Blackwood and Transfers are included at various stages in the learning process. It has been widely promulgated by the EBU and by EBUTA in particular, but the exact form is used mainly by those who have learned their bridge recently and those who taught them.
• Modern Acol: a broad term for modern systems based on standard Acol but adding some additional conventions, particularly transfers and alternative ways of playing opening two-bids, as described below. Varies between partnerships, but typically includes two-suited overcalls, cue bids, checkback Stayman, Jacoby 2NT and Roman Key Card Blackwood.
• Benjaminised Acol: recognising that strong two opening bids occur rarely, the 2 and 2 openings are used as weak two bids to show weak hands containing long suits. Very strong hands are shown by an opening bid of 2 which forces a 2 response allowing suits to be shown. The strongest hands are shown by an opening bid of 2.
• Reverse Benji: identical to Benji except that the 2 and 2 bids are switched in meaning. A 2 opening bid is now the strongest bid, as in basic Acol.
• Modern Acol with Three Weak Twos: uses the Standard American pattern where 2 is the only strong bid and 2, as well as 2 and 2, is a weak two bid. Proponents consider that a Benji 2 bid on 23+ or a game forcing hand is too infrequent to use up a whole opening bid. A weak two in diamonds is much more common. However, some definition may be lost on strong hands aiming for slam. The English Bridge Union's recommended teaching methods have changed from strong twos to three weak twos in recent years.
• Acol with Multi 2: this variant of Acol makes use of the Multi 2 diamonds convention, where 2 shows a variety of hands including weak two bids in hearts and spades. The 2 bid is used as in standard Acol. Various uses are made of the 2 and 2 bids, with traditional strong twos or Lucas twos being some popular methods.
• For options with a weak NT and five card majors or five card spades, see Alternatives.

  Standard Acol

Opening bids

• Special opening bids:
• * 1NT — Shows a balanced hand. Subject to partnership agreement, it may be either weak, strong or variable. Limit bid. The weak NT is by far the most common practice among UK club and social players.
• * 2 — Conventional game-forcing bid, promising game-going values and at least 5 quick tricks. Game forcing unless responder replies 2 and opener rebids 2NT.
• * 2 of any other suit — Strong two bid which shows a strong hand with at least eight playing tricks and a 6-card suit. Forcing for one round. Many players nowadays use weak twos or other alternatives - see Variants.
• * 2NT — Shows a balanced hand with 20–22 HCP. Limit bid.
• * 3 of a suit — Preemptive, normally seven or more cards in the suit bid, weak hand. Not forcing. 4 of a suit bids are similar but typically have at least an 8 card suit.
• * 3NT — Preemptive, shows a long solid minor suit and is called the Gambling 3NT
• Wide-ranging opening bid :
• * 1 of a suit — Promises a minimum of 12 HCP and a 4-card suit, 11 HCP and a 5-card suit, or 10 HCP and a 6-card suit. Not forcing.

Responses and further bidding

Responses to 1 of a suit

• Pass — less than 6 HCP
• 2 of opener's suit — at least four-card support and 6–9 HCP. Limit bid.
• 3 of opener's suit — at least four-card support and 10–12 HCP. Invites game if opener has requisite strength. Limit bid.
• 4 of opener's suit — at least five-card support for opener's major and 6–10 HCP, this is preemptive and to play.
• 1NT — 6–9 HCP, denies ability to bid at 2 level. Not necessarily balanced. Limit bid.
• 2NT — balanced, 10–12 HCP. Limit bid.
• 3NT — balanced, 13–15 HCP. Limit bid.
• 1 of a new suit — promises at least four cards in the suit bid, 6 HCP upwards. Forcing for one round.
• 2 of a new suit — normally 5-card suit, at least a good 8 or 9 HCP. Forcing for one round
• Jump in a new suit — 5-card suit, at least 16 HCP, Game force.