1. Convention Card
General Approach - Acol: Opening one of a suit shows 12+ pts and 4 cards in that suit.
Weak 1NT: Opening 1NT shows 12-14 HCP, balanced, without a strong 5-card suit, when not vulnerable, 15-17 HCP when vulnerable.
Strong 2-Club Opening: Opening 2C shows 23+ HCP or game. 2D negative response.
Stayman: next level club response, to NT opening, asks partner to bid a 4-card major or 2D with no 4-card major.
Double is generally takeout.
Weak 2's (2H-2S): 6 card suit 6-9 points. 2D shows 6-9 pts 5-4 in the majors either way
Weak Jump Overcall: Jump overcall shows, 6-9 pts, 6-card suit.
Gerber Over NT Bid: Same as in other systems.
Roman Key Card Blackwood: Same as in other systems.
Gambling 3NT Opening: Solid 7+ card minor suit. Little side strength. Responder can pass or bid correctable
See the topics below, for more detail.
1C: 12+ Points 4+ clubs 1D: 12+ Points 4+ Diamonds 1H 12+ Points 4+ Hearts
1S: 12+ Points 4+ Spades.
We treat a bid of either major as a 5 card suit when responding.
1NT: 12-14 Points Balanced hand.
Responces to 1NT: 2C -> Stayman, 2D -> H, 2H -> S, 2S -> C, 2NT -> D
2C: Strong forcing 23+ points or GF in a Suit
2D: Weak (6-9 pts) 5/4 in both majors.
2H: Weak (6-9 pts) 5+ Hearts.
2S: Weak (6-9 pts) 5+ Spades.
2NT: 21-22 HCP Balanced.
3NT: Gambling 3NT. Solid 7+ card minor suit. Little side strength. Responder can pass or bid 4C or 5C. If responder bid clubs, and opener's suit is diamonds, he corrects to 4D or 5D.
3 or 4 of a suit: Preempt. Weak hand. Long suit. Little side strength.
3. Responses To One Of A Suit
1/1: One-over-one shows 6+ pts, and a 4-card suit. Forcing for one round. Responder shows 4-card suits up the line, and 5- card suits down the line.
1NT: 6-9 HCP. Balanced. Denies any 4-card suit that can be shown at the 1-level. Denies 4-card support in partner's suit.
2/1: Two-over-one. 9+ HCP and a 5-card suit or 10+ HCP and a 4-card suit. Forcing for one round. 1S-2H shows a 5-card heart suit.
raise: 6-9 pts. 4-card support.
jump shift: 16+ HCP. Strong suit.
2NT: 11-12 HCP. Balanced. Invitational to game. No 4-card support.
double raise: Limit raise, 10-13 pts. 4-card support. Invitational to game.
3NT: 13-15 HCP. Balanced.
raise to game: 13-15 pts. 4-card support.
4. Rebids After One Of A Suit
To rebid a suit, you need a strong 5+card suit. A minimum bid (not a reverse) in a new suit shows minimum values.
5. Variable 1NT (or Weak 1NT)
Opening 1NT shows 12-14 HCP, balanced (4-4-3-2 or 4-3-3-3 or 5-3-3-2 without a strong 5-card suit), without a strong 5-card suit, when not vulnerable, 15-17 HCP when vulnerable. Most Acol players now use a weak (12-14) 1NT. Some use a strong (15-17) 1NT (especially in Canada where some people play Colonial Acol).
Responses to a Weak 1NT (for the point-ranges for responses to a strong 1NT, see my article on Standard American):
2C: Stayman, showing 11+ pts and a 4-card major. See below.
2 suit: 0-10 pts. 5-card suit. Unbalanced. Signoff.
2NT: 11-12 HCP. Invitational to 3NT. Balanced. Opener bids 3NT with a maximum (16-17 HCP).
3 major: 11+ pts? 5-card major. Forcing to game. Opener raises with 3-card support.
3NT: 13-18 HCP. Balanced.
6. Non-Forcing Stayman
A 2C response to a 1NT opening is Stayman, the method for finding a 4-4 fit in a major in this situation. It shows 9+ pts (following a Weak 1NT), and at least one 4-card major. It is forcing, and asks partner to bid 2S with a 4-card spade suit, but no 4-card heart suit; or 2H with a 4-card heart suit, and maybe a 4-card spade suit; or 2D with no 4-card major.
Responder's next bid, after Stayman (for the point-ranges for responses to Stayman after a strong 1NT, see my article on Standard American):
1NT-2C-2D:
2NT 11-12 HCP. Invitational to game.
3C 0-10 pts. Signoff.
3NT 13+ pts.
1NT-2C-2 major
2NT 11-12 HCP. Invitational to game.
raise 11-12 pts. 4-card support. Invitational to game.
3C 0-10 pts. Signoff.
3NT 13+ HCP. Less than 4-card support.
raise game 13+ pts. 4-card support.
3C over a 2NT opening bid is either Stayman (forcing to game) or Baron, depending on partnership agreement. Baron asks opener to bid his 4-card suits up the line.
7. Strong 2C
An opening bid of 2C shows 23+ HCP or game, and is virtually forcing to game. 2C is an artificial bid, as it bears no relation to opener's club suit.
Responses to 2C:
2D: Negative response, 0-7 HCP (& 2NT second negative?).
new suit: Positive 7+ HCP. 5-card suit.
2NT: Positive 7-9 HCP. Balanced. May have a weak 5-card suit.
3NT: 10-12 HCP. Balanced.
Further bids of new suits show 5-card suits then 4-card suits. Rebid of a suit shows 6 cards. 2C-any-2NT shows 23-24 HCP and is not forcing. 3C is now Stayman.
8. Acol 2-Bids (Intermediate 2-Bids)
An Acol 2-Bid (Intermediate 2-Bid) (2D-2S) shows 8 tricks and a strong 5-card suit, and is forcing.
The responses:
2NT: Negative, 0-6 HCP.
new suit: 7+ HCP. 5-card suit.
raise: 7+ HCP. Support. Probably one ace.
double raise: 7+ HCP. Support. No ace.
3NT: 10-12 HCP. Balanced. No real support.
Any of the positive responses is forcing to game.
9. Preempts
3 or higher in a suit. See my article on Standard American 5-Card Majors.
10. Competitive Bidding
The main difference between Acol and Standard American, when it comes to competitive bidding, is the Intermediate Jump overcall. This overcall shows 12-16 pts, and a 6-card suit. The jump is used to show length, rather than hand strength. A Weak 1NT opening bid can be overcalled (with about opening strength) or doubled for penalties (with 15+ pts) more readily than a Strong 1NT.
11. Slam Bidding
See my article on Standard American 5-Card Majors.
12. Forcing Bids
In Acol, both the opening 2C bid and the Acol Two-Bid are forcing opening bids. Other forcing bids are the same as Standard American.
13. Popular Options
A few popular conventions, commonly used with Acol:
Baron: 2C response to 1NT opening bid, or 3C response to 2NT opening bid, asking partner to bid 4-card suits up the line. 2C Stayman response to 1NT is more popular.
Benjamin: A popular way of using Acol 2-bids with Weak 2-bids. A 2C opening is an Acol 2-bid (intermediate) in some suit. An opening 2D is the equivalent of a Strong 2C opening. And 2-of-a-major is a weak 2-bid.
Flint: Weak 3D response to 2NT opening bid forces opener to bid 3H, after which responder passes or signs off in the contract he desires.
Swiss: A leap in a new suit to show support, game values, and some
And others (like Splinters or Jacoby Transfers or Jacoby 2NT).