players will have a perfect score. In round 2, if #5 and #6 score upset wins against #3 and #4, and there is a decisive result between #1 and #2, there will be three players with a perfect 2–0 score. Danish system The Danish system works in principle like a Monrad system, only without the restriction that no players can meet for a second time, so it is always #1 vs. #2, #3 vs. #4 etc. Bridge team tournaments, if not played as "Round Robin", usually start with the Swiss system to make sure that the same teams would not play against each other frequently, but in the last one or two rounds there may be a switch to the Danish system, especially to allow the first two ranked teams to battle against each other for the victory, even if they have met before during the tournament. This would be more common if relatively few teams are involved. In a large field it is usually easy to match high-scoring teams who have not previously met. Grand Prix system In a few tournaments which run over a long period of time, such as a tournament with one round every week for three months, the Grand Prix system can be used. A player's final score is based on their best results (e.g. best ten results out of the twelve rounds). Players are not required to play in every round; they may enter or drop out of the tournament at any time. Indeed, they may decide to play only one game if they wish to, although once a player wants to get a prize they need to play more rounds to accumulate points. The tournament therefore includes players who want to go for a prize and play several rounds as well as players who only want to play an off game. McMahon system A variant known as the McMahon system tournament is the established way in which European Go tournaments are run. This differs mainly in that players have a skill ranking prior to the start of the tournament which determines their initial pairing in contrast to the basic Swiss-system approach where all players start at the same skill ranking. The McMahon system reduces the probability of a very strong team meeting a very weak team in the initial rounds. It is named for Lee E. McMahon (1931–1989) of Bell Labs. Amalfi system