This page will be used to draw player's attention to any matters relating to the "Rules", and also particular matters that have arisen during play which all players should be aware of.

BUTLER IMP SCORING  -  PLAYING TACTICS~

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Ever wondered what the “IMP” table at the bottom of the left hand side of the scorecard is used for?     If you’ve played in Teams you will know.     Otherwise, you will find out next Monday!~

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Next Monday (18 May) we will play a “Butler IMP Scored” session.~

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In a “Duplicate Pairs” session, you try to get a higher score on each board than all the other corresponding pairs (N/S or E/W).    You get two Match Points for each pair you beat – so you strive to get a “top”.   And only the ranking of the scores matters – not the size of the scores.   (A top is still a top even if it is only 10 higher than the next – and so on down the order.)~

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In a “Butler IMP Scored” session, it’s the magnitude rather than the ranking of your score which counts.   You are awarded IMP points (IMP = International Match Point) for how well your score compares with the “average” score on each board.~

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As an example, 3 out of 10 NS pairs make 4S (non-vulnerable) = 420, 1 pair make 3NT+1 = 430, 1 pair make 4S+1 = 450, 4 pairs go 1 off = -50 and the other pair go 2 off = -100.     In taking an average, the highest and lowest are ignored (on the basis that these may be “freaky” scores), and the average is taken of the other scores – in this case giving an average of +185 (roughly) – rounded to +190.    Those who got 4S got 230 more than the average, and this is converted on the IMP scale to +6 IMPS.    The pair who got 3NT+1 got 240 more than the average, which is still +6 IMPS difference, and the pair who got 4S+1 got 270 more than the average which is +7 IMPS.     Those going 1 off were 240 worse than the average = -6 IMPS; and the pair going 2 off were 290 worse than the average = -7 IMPS.     (And the EW opponents get the opposite scores;  +6 NS gives -6 EW.)~

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The different method of scoring using IMPS does benefit from different tactics to those used when playing match pointed events (which most people will be more familiar with).~

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The above example illustrates some of the tactics.     Getting the extra trick in making 4S+1 did get some reward compared to getting the straight 4S – but only 1 extra IMP in this case.    Those going down, on the other hand, were penalized heavily.    Moral:   Make sure you get a game contract.     Overtricks made little (if any) difference to IMPS.     So play safe to get the contract rather than take chances to get an overtrick.    If the gambles don’t pay off, you may go down and be heavily penalized for it.~

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Also in the above example, 4S and 3NT+1 both scored the same +6 IMPS – which seems fair as both made 10 tricks.    3NT would have still scored +5 IMPS – only 1 less.      In match pointed scoring, the difference between 3NT,4S and 3NT+1 would be significant.  In IMP scoring, the difference between 400, 420 and 430 has little effect.     Moral:   It’s not important to go for the highest scoring game contract.     Go for the safest one – and make sure you get it.~

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Summing up the tactics that emerge from the above:~

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If there is a game contract to be made, it is essential to bid it.~

And if you do bid a game contract, make sure you get it.~

Play safely.    Never risk a contract for the sake of an overtrick.~

When there is a choice of game contracts, bid the safer one.~

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Vulnerability~

The differences between:    getting a game contract    and    going 1 down~

and between:   bidding a game contract  and   not bidding it~

are both more in vulnerable situations than in non-vulnerable.~

So the tactics above especially apply when vulnerable.~

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Bidding “thin” games.~

Although the tactic is to bid and play safely when there is a clearly a game contract to be made, some game possibilities will not be so clear-cut.    If, for example, there are thought to be 14 ½ losing tricks between the two hands, there is probably a 50/50 chance of making 3S or 4S.   You have a choice of staying in a safe 3S or going for a chance game in 4S.~

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The average score in this situation is probably going to be around the +170 mark.  (Half the tables will bid 4S; only of those half will make; the others will stay at 3S, some making +1).    If you bid 4S vulnerable and make it, you will gain around +10 IMPs.   If you go 1 off, you will lose 7 IMPs.    Now, +10 vs –7 are not bad odds for a 50/50 chance.    If, however, the hand is non-vulnerable, the potential gain is only 6 IMPs against a potential loss of 6 IMPs – which is no better than the 50/50 chance.~

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So, if vulnerable, bid games which have a 40% chance of making.~

If non-vulnerable, be at least 50% sure the contract will make.~

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Sacrifices~

A sacrifice may reduce the points scored by the opposition, and so produce a better score.   In match point scoring, if 4S vulnerable is generally bid and made, but you sacrifice 500 instead of letting them get 620, that sacrifice may get you a top.   But in Butler IMP scoring, it will only earn/save you around 3 IMPs.    On the other hand, if the 4S which you sacrificed against was not generally makeable anyway, your sacrifice could lose you around 10 IMPs.~

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So, be less inclined to make risky sacrifices.~

Be certain that the contract you are sacrificing against is going to make.     Against vulnerable game contracts, don’t risk going more that 2 down non-vulnerable or 1 down vulnerable.    When in doubt, leave the contract and hope to get it down.~

If the opponents sacrifice against your game, and you are in doubt about whether to bid higher, double and take your sure plus score.~

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Part score competitive bidding~

The scores involved with part score contracts are not as large as when game contracts are involved – so the potential IMP scores are also less.     (Overtricks, and the differences between minor and major suits and NT, are still not significant – so still bid the safest contract and play safe to make the target tricks.)    But going down doubled after unsuccessfully trying to push the opponents up can badly backfire.    E.g.   Other pairs trade-off 2 or 3 IMPs – you go down 1 vulnerable doubled and lose 5 IMPs.      ~

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So, be cautious in a part score bidding contests – especially when vulnerable.     ~

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Doubling~

You double a non-vulnerable 4S contract; they go 1 off; you gain an extra 2 IMPs.    But if they make the contract, the double has cost you 5 IMP.     Generally, you stand to lose more than you gain by doubling.     And the same applies to doubling a close part-score contract.   (And don’t forget that by doubling you tell the declarer where the danger lies – thereby helping him.)~

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So, only double if you expect to take the contract at least two off.~

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Slams~

Because of the high scores involved, getting a slam when not all other pairs bid it or get it can gain a big difference in IMPs.     Equally, not bidding bidding/getting a slam when others do can lose a lot of IMPs.~

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So, if a slam is on, make sure you bid it.~

Having bid a slam, don’t go down.    Play safe.~

Don’t bid dodgy slams which go off.~

Settle for small slam rather than risk an unsure grand slam.~

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Defending~

Remember the that over-tricks don’t matter when defending also.   If you have a line of defence that might get the opposition down if you are right, but will give them over-tricks if you are wrong – then go for it.     Your potential gain is far greater then your potential loss.~

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In summary the winning tactic with IMP scoring is generally :~

BID BOLDLY  -   PLAY SAFELY~

ENJOY