Theory and Conventions



M J Bridge



Pairs, teams, or rubber

Most competitive bridge clubs play a form of bridge known as ‘duplicate pairs’ on ordinary club nights.

Many tournaments and leagues are based on ‘teams’ play and scoring.

Bridge played at home, or among any group of four, is more likely to be ‘rubber’ bridge or ‘Chicago’.

Although these are all essentially the same game with similar rules and scoring there are significant differences, particularly in the ways in which the scores are combined.  These differences will in turn affect both your bidding decisions and strategy.

Rubber bridge and Chicago

In both rubber bridge and Chicago there is no one to compare your score with and so a gain of just a few points is neither here nor there.

By way of contrast there are significant bonuses for bidding and making game and slam contracts - you should aim not to miss out on these.

There is also the consideration of part-scores combining to make a game, which does not feature in the other form of the game.

This site is not primarily concerned with rubber bridge or Chicago.  The methods discussed on this site can be used in the same way in these forms of the game, although some of the more advanced conventions may well be unnecessary and indeed inappropriate in a ‘friendly’ family game, but there is no discussion of the specific considerations when making your bidding choices.  In particular, at no point on this site are part-scores considered as a building block for a possible game - each deal is considered as an entity in itself.

Duplicate pairs, or ‘match-pointed pairs’

In this form of the game, your score on every board is compared with that of every other pair playing the same cards.  Whoever gets the best score on the board is awarded the points for a ‘top’.  It doesn’t matter if that top is 800 more than the next pair, or just 10 more - it is still a top and will score the same maximum points.  Every board is equal.  If you were to play 25 boards in a club evening then each board would be worth the same potential 4%.

It follows that frequency of success is the important factor - not the size of the win.


if a heart contract is likely to make nine tricks 55% of the time and ten tricks the other 45% then 3 will be the correct contract rather than 4 - it will lead to the greater frequency of positive scores;

if both hearts and no trumps are likely to make ten tricks then 3NT is the optimum contract scoring 430 rather than 420 (when not vulnerable);

if hearts are making ten tricks and no trumps are making just nine tricks then 4 is the place to be scoring 420 rather than 400;

if you can make 2 for 110 when everyone else is bidding and making 1NT for 90, then the spade contract is to be preferred

(note though that if everyone else in the room were to make 8 tricks in no trumps for 120, your 110 would suddenly becomes a bottom;

taking the opponents down for 100 will score considerably better than bidding and making 1NT for 90 - competing for one more will frequently not be the correct action;

even doubling your opponents into game will be the right action at pairs if you get a top by taking them down (for 200 say) more often than you double them into a making game for a clear bottom (-590 say) (51% of the time will do, in theory) - note that such an action would be unthinkable at teams scoring (below).

There are just a few circumstances in which you might choose to play in a low probability contract at pairs scoring, and that is to do with the concept of ‘playing the room’.

If you think that you are likely to be in a different contract from the rest of the room then it will sometimes pay to make a safer play to ensure that you bring your contract home - this will particularly be the case when you have bid a game contract (say) which you suspect might not have been bid at every table,

and conversely it will sometimes be correct to risk everything to make a contract, because anything else will probably score a bottom anyway - on one occasion my partner (quite reasonably) took me out of a 3NT contract which I knew was likely to make ten tricks and put me into five of a minor.  I raised to six - it was our only chance of a good score, however thin the chances.  On that occasion - the one I remember - it worked.

Teams, or imps (International Match Points)

Typically a team will consist of two pairs.  On each board one pair in the team will play the N/S cards at one table, and the other pair will play the E/W cards against the other opposing pair at a second table.  The two scores are then combined to produce a ‘swing’ on each board which may or may not be converted on a standard scale into ‘international match points’ (imps).  This time the size of the win or loss is critical.

If a particularly accurate piece of bidding leads you to make ten tricks in spades whilst your opponents make only nine tricks in no trumps then your team will score a swing of 20 points (420 -400 or 620 - 600).  In a pairs competition those extra 20 points might have ensured a top, but in teams it converts to just 1 imp - usually neither here nor there.

On the other hand, if you make ten tricks in 4 whilst your other pair hold the opponents to nine tricks (also in 4) on the same cards, then non-vulnerable your side will score a swing of 420 + 50 = 470 which will convert to 10 imps, and vulnerable the swing will be 620 + 100 = 720 which will convert to 12 imps.

Your methods should therefore be tailored towards locating the high scores - contracts at game-level or higher, or substantial penalties for doubled contracts.  Small losses for failure to make an extra overtrick or for being in less than the optimum part-score contract are of relatively little significance.

In this form of the game you will bid ‘thin’ games in search of ‘a swing’, but you will eschew risky plays which might make an overtrick in favour of a safer play which ensures the contract.

Decisions at the table

These factors should affect your decisions at the table.

Suppose a certain bid or play is likely to earn you an extra 30 points on 55% of occasions, but risks losing 200 on the other 45%.

Broadly speaking, in pairs, it will be right to make that bid or play.  In the course of 20 boards you would hope to get 11 good scores to set against 9 poor ones, and that must be good bridge.

At teams, though, this same bid or play will gain you 1 imp on eleven occasions but it will lose you 5 imps on 9 occasions - a net loss of 34 imps - bad bridge.

For a second example, suppose you are thinking of bidding a thin game - perhaps a contract which has about a 40% chance of making.

In pairs it would be poor bridge to bid such a game contract - be content to get a good score six times out of ten.

In teams however, it is another matter.

Vulnerable you will score 620 in 4 whilst your opponents score 170 for 3 + 1, a gain of 450 and 10 imps four times out of ten.  On the other six occasions you will score -100 whilst your opponents score 140 - a loss of 240 which is 6 imps.   Net gain +40 - 36 = +4.

Not vulnerable the break-even point is around 45%.

In either case it is significantly less than 50%.

Similarly, in pairs a penalty double of a vulnerable 2 bid is good bridge if you are going to take the contract down more than half the time - +200 for one down is likely to score you a top on a part-score hand.

But at teams, such a double would be suicidal  To give your opponents 670 instead of 110 is 11 imps, and that can swing a whole match.  In fact the probability of taking it down needs to be around 80% before you even consider such a bid.

So at pairs you will usually take a risk (50% chance or better) to make an extra overtrick, or to hold your opponents to one less than the norm, in the search for that ‘top’,

but in teams you will make the safety play and ignore the possibility of an overtrick.

Bidding methods

For most of us this will not be a consideration, but if almost all of your bridge is played at duplicate pairs scoring then your system should emphasise methods which are likely to help you compete to the best part-score just as much as those which aim to locate games and slams.

It may seem surprising, but in pairs play accurate bidding (and play) in the part-score zone is just as important as bidding and making the difficult slams.

Conversely, if most of your bridge is played at teams scoring then you might prefer to choose methods which occasionally lose accuracy in the part-score battle as you strain to get the big contracts right.


And, just as an afterthought, if you have not tried teams play give it a try - it is a different challenge and one which many find quite addictive.

You will usually find that your county association will run a league catering for teams of differing standards and experience.

However, for the moment, I am just pointing out why the bidding advice throughout this book will , not infrequently, draw a distinction between a pairs bid and a teams bid.

This page last revised 6th Jan 2020