Acol

Four-card majors

An Acol player opens a four-card major in preference to a three-card minor. With 4-4 in the majors and a minimum, open the lower — 1♥ — leaving room to find spades later.

What it buys: 4-4 major fits are found immediately rather than through a sequence that may never get there.

What it costs: the opening bid no longer guarantees five, so responder needs four-card support to raise, and the partnership occasionally plays a 4-3 fit.

The weak notrump

1NT shows 12–14 balanced. That makes it the most frequent opening bid in the system: a great many ordinary hands are balanced 12-counts, and in Acol they all get described in one call.

The knock-on effect surprises Standard American players. Because the weak notrump takes the 12–14 balanced hands, a one-of-a-suit opening followed by a notrump rebid shows 15–16, not 12–14.

Every rebid's strength band shifts by a full range, which is why you cannot adopt four-card majors and a weak notrump piecemeal.

The two-level openings

Classic Acol used strong Acol two-bids: 2♦, 2♥ and 2♠ all showed powerful single-suited hands about a trick short of game, forcing for one round.

Modern Acol has mostly abandoned them in favour of weak twos, with 2♣ as the single strong artificial opening.

Read an older book, then sit down with a modern partner, and this is the difference that bites first.

What does not change

Most of what this blog covers applies unchanged. Acol partnerships play Stayman, transfers, takeout doubles, negative doubles and Blackwood the same way.

The scoring is the same, the play is the same, the judgement is the same. A system is a set of agreements about what opening bids and rebids mean — a smaller part of bridge than the amount written about it suggests.

Acol or Standard American?

Mostly a question of where you play. Acol is standard in Britain, Ireland, Australia and New Zealand; Standard American and two over one dominate in North America. Online you will meet both, and most robots bid a five-card major system by default.

Neither is measurably better. Four-card majors find more 4-4 fits; five-card majors give responder more reliable information. The weak notrump describes more hands in one bid and is riskier when doubled. Serious partnerships win with both.

The one rule that does matter: pick one and play it properly. A pair where one player opens four-card majors and the other expects five will misjudge a trump fit on the first board and keep doing it.

Where the name comes from

From the Acol Bridge Club in Acol Road, Hampstead, where the system was developed in the 1930s by a group including Maurice Harrison-Gray, Jack Marx and S. J. Simon.

It was meant as a natural, judgement-led alternative to the heavily systemised American methods of the period. That character, fewer rules, more judgement, is still what its advocates like about it.