Editing Duplicate bridge (section)

===Scoring and tactics===
The type of scoring significantly affects a pair's (or team's) tactics. For example, at matchpoints, making one more overtrick than everybody else on a board gives the same result (the top) as making a slam that nobody else bid, whereas at IMP scoring, the difference comes down to 1 IMP (30 points) in the first case, but 11 or 13 IMPs (500 or 750 points) in the second case. In general, matchpoint scoring requires a more "vivid" and risk-taking approach, while IMP scoring requires a more cautious approach. People that dislike IMP scoring sometimes refer to it as "cowardly", while people that dislike matchpoint scoring sometimes refer to it as "not bridge". The main features of the tactics are:
* '''Matchpoints'''
** Overtricks are important.
** [[Safety play]] is often neglected in the hunt for overtricks.
** Thin [[Contract bridge glossary#G|games]] and [[Contract bridge glossary#S|slams]] are avoided.
** [[Sacrifice (bridge)|Sacrifice]]s are more frequent; e.g. going down 500 points on a doubled contract is a good result if the opponents can score 620 points for a game.
** [[Contract bridge glossary#P|Penalty doubles]] are more frequent, as they increase the score for the [[Contract bridge glossary#P|penalty]]. For example, "the magic 200" refers to the situation when a vulnerable pair's contract is doubled and goes one down &mdash; the score of 200 will outscore almost all part-score contracts played at other tables.
** Playing in higher-scoring [[Contract bridge glossary#D|denominations]] (notrump or [[Contract bridge glossary#M|major suits]]) is important, as it may lead to an extra 10 or 20 points.
** Due to the above, it is often unclear to the defence, and sometimes even to declarer, what their goals are.<ref>Kelsey, H.W.: "Match-point bridge", Faber's "Master Bridge Series", 1970</ref> Thus mastering matchpoints play requires additional skills (sometimes referred to as "not bridge" by those who dislike it) to those required to play IMPs.
* '''IMPs'''
** Overtricks are not important, and it is not worth a significant risk of losing a game bonus of 300–500 points = 8–11 IMPs (or to a lesser extent a part score of 110 to 190) for the potential 1 IMP gain for an overtrick.
** [[Safety play]] is very important, for the same reason.
** Thin [[Contract bridge glossary#G|games]] and [[Contract bridge glossary#S|slams]] are often bid. Bidding a [[Contract bridge glossary#G|game]] with 40 percent [[probability]] of success vulnerable and 45 percent nonvulnerable, or a small slam with 50 percent probability, is worth the risk, and anything over that increases the probability of a positive IMP score in the long run.
** [[Sacrifice (bridge)|Sacrifice]]s are less frequent, as they may be risky and the relative gain can be less. Conceding -500 points rather than -620 if you might have got the opponents down for +100 is less worthwhile. However, if you can hold the penalty to -100, this is attractive.
** [[Contract bridge glossary#P|Penalty doubles]] are less frequent, as they may be risky. Often, when an opponents' contract is doubled, it turns declarer's attention to the bad lie of cards, and may induce him to take a successful line of play that he would not take otherwise.
** The contract itself sets a clear goal for both the defence and declarer, frequently allowing a deeper level of counter-plays between them.