Acol is the prominent bidding system used in England and has been played widely in New Zealand for many years. Its name comes from the road where the Acol Bridge Club used to be in West Hampstead, North West London. The system was initially devised by a group of keen players at that club in the early 1930's though is a system which continues to develop.
Its underlying principle was to keep the bidding as natural as possible. We shall look here at Acol in its purest sense though even by suggesting that one opens the lower of two four card suits or plays Weak 2 Opening Bids, we could be accused of moving away from basic principles.
These are the corner-stones of the system we shall examine:
- Opening four card suits
- 1NT opening is 12-14
- Limit Raises
With any evolving system, how the Acol system started is no longer the way we see as the best practice. The following discussion will still retain the above principles but adapts them to better usage.
Opening Four Card Suits
It is deemed a basic principle of Acol that you will always open, at the one level, with a suit of at least 4 cards. You must have at least one such suit. If you have more than one, you open the lower ranked suit unless you have 12-14 hcp (and no singleton) in which case you open 1NT.
The point range varies slightly depending on whether you are opening a 4 card, 5 card or 6 card suit.
- 4 card suit 12+ hcp
- 5 card 11+hcp.
- 6 card 11+ or if a good hand 10+hcp.
The maximum point count is 19 though in each of the above hand types, some 20 point hands, not good enough for a game-forcing 2♣ opener and which cannot be opened 2NT (20-22) should be opened at the one level.
Thus, you open 1♠ with any of the following hands:
Notice, with only a 4 card suit, North will have at least 15hcp, or would open 1NT.
5 card suit, 11 hcp
It is wrong to open a weak 2♠ on two counts. It has too much potential playing strength and it has a good 4 card suit in the other major, both making 2♠ a poor choice of opening bid.
Although a 20 count, the singleton king, a poorish 6 card suit and 6 hcp in diamonds possibly tied up in just 2 winning tricks, all make this a 1 level and not a strong 2 level opening bid.
1NT Opening 12-14 hcp
In traditional Acol, this bid could contain a 5 card minor in a balanced hand but not a 5 card major. However, one important criteria of opening one of a suit is that you must have a sensible rebid. Opening 1♠ on the following hand would be a mistake as the spade suit is far too weak to rebid if South replies 2♥.
It is better to open this hand 1NT.
When you open a 12-14 hand 1NT, you need to have a good method of escape if the opposition double for penalties. The traditional approach then was that redouble by one’s partner asked opener to bid their lowest 4 card suit (you would never play redouble as a strength showing bid) and that any suit bid by responder was a 5+ card suit, to play, even a 2♣ bid.
However, transfers have become common-place without an opposition double and quite common with it. It is important both partners are on the same wavelength. Without transfers, the sequence:
showed 5 hearts and forced opener to choose between 3NT and 4♥. The transfer bids now give a better way to bid such a hand.
Requirements of 1NT opener
To be clear, when you open 1NT, you must have at least 2 cards in each suit, 12-14 hcp, generally no 5 card major and no more than one suit of 2 cards. That makes the following 1NT openers:
You cannot have a hold in every suit. No worries. Your partner can help you out.
Having a 5 card minor in a balanced hand is fine. But here you must open 1♣ because you only have one diamond.
After opening 1NT
Most pairs play transfers after 1NT opening, at least using 2♦ and 2♥ showing the suit above. The 2♣ response is Stayman and 2♠ a range-finder. These are the common responses which help you to find whether you have a major suit fit and whether you should be in game or part-score.
Playing 4 card suit openings, you need 4 trumps to support your partner initially. With 6-9 hcp and 4 card support, you raise partner to the 2 level. With 10-12, you raise to the 3 level. You only support your partner’s minor suit opening if you do not hold a 4 card+ major.
After responder’s point showing response, the opener can often place the correct level of the contract. Hence:
After 2♥, North can calculate their partnership has enough hcp for game. If North were weaker, they would either invite with 3♥ or pass 2♥, depending on their point count and perhaps their shape.
No support for Opener's suit.
With 6+ hcp, responder bids their longest suit, though can only bid a new suit at the two level with 10+ hcp. These are not limit bids as responder could have 6 or 16 hcp. Opener does not know and therefore must bid a second time.
However, if responder is in the 6-9 hcp range and cannot bid their suit at the 2 level (as stated above), they bid 1NT, a definite limit bid.
Here, both responder, then opener make limit bids. 1NT is 6-9 hcp with less than four cards in either major. 2♦ shows 5 hearts and 4+ diamonds in a hand with 12-17 hcp. With 18 or 19, North would have bid 3♦.
As North could have up to 17 hcp, South, with diamond support, raises to 3♦. Were North stronger they might try 3NT or 5♦ but they have minimum strength and therefore pass what should be a safe 3♦ contract.
It is important to understand the difference between a limit, an invitational and a forcing bid. Where a bid has an upper limit, then it is not forcing, unless the partnership is known to have enough hcp for game. Take the following:
2NT, a limit bid, is forcing to game since South is known to have 10+ hcp. 2NT shows 15-17 hcp. South’s 3♥ is unlimited in strength and checks to see if North has 5 hearts. Hence, the heart game is found rather than 3NT, which would be very risky on a club lead.
Other Traditional Acol Bids
There are other hallmarks of traditional Acol. The virtual Game Force 2♣ and 20-22 balanced 2NT openings remain today as strong bids. Other strong 2 level openers (called "Acol 2s") have given way to weak 2s while strong jump shift responses (15+ hcp) have given way to weaker or other uses because they occur so rarely.
Acol has cornerstones as indicated above but is a constantly changing system. That makes it an interesting system to play.