I'm sure a lot of you know all this anyway but I just wanted to make it clear for everyone so we're all in the same place. I'm assuming either Duplicate or Chicago scoring. It might be an idea to have a clearer idea of just exactly what you'll score when you're in a contract, rather than being pleased - or horrified - after the event. So here's a small resume of what goes on.
You get the trick value PLUS a part-score bonus of 50; a game bonus of 300 or 500 and slam bonuses of 500 & 1000 NV and 750 & 1500 Vul.
You need to win the first six tricks before yyou score anything and after that the trick values are:
- minors (clubs & diamonds) - 20 per trick
- majors (hearts & spades) - 30 per trick
- no trumps - 40 for the first scoring trick, 30 thereafter
- 3 Clubs bid and made (nine tricks) is 110. This is composed of 60 (3x20) for tricks and 50 bonus for a successful part score.
- 2 Spades bid and made (eight tricks) is 110 - 60 (2x30) +50. An example of why we prefer Majors to Minors.
- 3NT not vulnerable making exactly (nine tricks) is 400 - 100 (40+30+30) +300 bonus for the non-vulnerable game.
- 3NT Vulnerable (same nine tricks) is 600 - 100 (40+30+30) + 500 bonus for the vulnerablel game. An example of why we take the odd risk to bid a vulnerable game - it's worth more.
You don't always succeed however. Sometimes the horrible opponents defeat you and then they score points instead of you. If you are not vulnerable they score 50 for each trick by which you fall short, while if you are vulnerable this penalty is increased to 100 points an 'undertrick'.
Sometimes the smart alec opponents smugly think in advance that they are going to defeat you and have the temerity to 'double' your contract. If you make it you score double trick points AND you get an additional 50 'for the insult'. I won't bother with all the doubled and making scores as it's not the most exciting bed-time read you'll ever have. Just know that making a doubled contract is ALWAYS good.
However when the opponents have made a wise double, the penalty scale goes up - and well, if you have been rash, the scale gets horrendous. The first undertrick is just doubled in value of the penalty but then the subsequent undertricks cost more and more. The main thing to note is that if you go down two doubled when they can make game the vulnerability is crucial. If nobody's vulnerable you lose 300. That would be a bargain as they can make 400 or 420 for their game. You have a net gain. If they are vulnerable and you are not, you lose 300 against 600/620. An even bigger net gain. (In fact now you can afford to go 3 down for 500 and still gain!). BUT if you are vulnerable and they are not and you go 2 off doubled, you will lose 500 to save 400 or 420 - a net loss. On the other and, if everyone's vulnerable then 2 down doubled for 500 is OK against their possible 600/620.
At the part score level vulnerability is again crucial. If you're doubled, vulnerable and go 1 down losing 200 to save 140, it's obviously bad business.
The rule is "Always Know the Vulnerability!"