The first two articles have shown some ways that tournament play attempts to eliminate the "luck of the deal" in competitive bridge. The second article introduced the notion that the scoring systems affect the approach to bidding and play and showed a couple of examples emphasising bidding. This final article shows how the scoring system can influence the play of the hand.

At matchpoints a person can be a successful competitor for an entire lifetime without ever encountering or executing certain techniques. Chief amongst those is the safety play. A very important technique for teams events, safety plays are almost unheard of in pairs competitions and the reason is entirely a consequence of the scoring.

Recall from the previous article that overtricks are important in matchpoint competitions whereas at IMP scoring they hardly matter at all. Now consider the following hand ...

6 5 4
9 8 6
Q J 8 7
A 3 2
 
A K J 10 9 7 3
A K 5
6 2
4

You are playing in a vulnerable 4♠ contract. The opponents cash a top diamond and then switch to a club to knock out the Ace. The contract looks pretty good. On a normal 2-1 trump break you can draw trumps, lead a diamond to the Q, establishing the J as a winner and re-enter dummy with the third trump cash it. That will yield 11 tricks.

What could go wrong? If the trumps are 3-0 then there is a trump to lose along with the two diamonds and also a spade because there is no entry to dummy.

Is there any way to make the contract in the face of a 3-0 trump break? If West has ♠ Q 8 2 then no but if East has three trumps then you can make certain of 10 tricks. Simply finesse trumps on the first round. If the finesse wins then you are home with 7 spades, 2 hearts and a club. If it loses then it means the trumps are breaking and dummy's third trump will provide the required entry for the diamond winner which you will establish.

So how does the scoring influence the play?

78% of the time the trumps will break 2-1. In those cases the simplistic play of laying down the ♠A and ♠K will yield 11 tricks. If you were to make a safety play by taking a losing trump finesse on the first round then you would get a cold bottom at matchpoints because everyone else is making an overtrick. You risk coming out behind the field most of the time.

At IMP scoring the story is very different. The overtrick is not worth much, one IMP at best. Going down is catastrophic, costing 12 IMPs.

At rubber bridge the considerations are similar. The safety play guarantees a $6.20 win. The naive play stands to gain an extra 30 cents but could mean a $1 loss instead. Hardly worth it.

Do you care now?

There are other techniques which come into play more often at IMP scoring than at matchpoints but this is sufficient. If you are content to play in duplicate games and enjoy your weekly tournaments as a purely social event then no, you don't care. If you are at all interested in improving your bridge play then surely being exposed to hands which extend your experience is a good thing. That doesn't happen at matchpoints with its distorted scoring system actively discouraging certain plays. If you are ever going to compete at higher levels, even play in district teams events, then you do care.

IMP scoring at weekly duplicate events

Teams events are rather complicated things for tournament directors to arrange and are not really practical on a regular basis. Fortunately there is a workaround, trivially simple now that we have computers to do our scoring for us. Just score the Mitchell tournaments using IMPs instead of matchpoints. It doesn't have to be done every week but it should be done fairly regularly so that people get used to it. About once every three weeks seems about right. We get all the benefits without any downside.

No, with IMP scoring there is no such performance measure as a "percentage". But what does it mean anyway? Matchpoint tournaments are won with 59% or 69%. Is the difference really so important?

Some have complained that no other clubs score duplicate tournaments in IMPs. That is wrong. Other clubs have started doing exactly that but even if the assertion were true, who said we cannot be leaders? Is there some merit in always being followers?