GAMEPLAY

Generally speaking, the game of Bridge consists of two phases - a bidding phase and a playing phase. During the first one, players declare what number of tricks they will get and what suit they want their trump to be. During the other one, they try to get the tricks declared (declarers) or prevent the declarers from getting the tricks (defenders).

BIDDING

When players are dealt cards, it is time for bidding. Players offer specified numbers together with suits. The number in bidding is the number of tricks a player declares to take (with his partner) in this deal. It is always 6 tricks plus the declared number, e.g. 4NT means 10 tricks (6+4). The other number always declares a card suit. The suit of a suit depends on bidding hierarchy. It is presented below:

Clubs	The lowest suit
Diamonds
Hearts
Spades	The highest suit, but not during the bid
NT (No Trump)	Highest bid - means that will not be a trump suit

It means that the first player may bid as much as he wants. But the other players may bid only the same number with the higher suit or lower suit with the higher number, e.g. after 1 next player cannot bid 1 - if he wants to bid clubs, he must offer 2, during the bidding players may also PASS. Generally passing means that a player does not bid at the moment (But only generally, there are different bidding conventions. For further details you can refer to CONVENTIONS section). If a bid is misunderstood by opponents, there is an Explain button available. Then the chat is available for explaining the bid. (Note that this information is not available por the partner. It is based on a fact that both players probably realize the meaning of the controversial bid.).

Points gained for:

Tricks (underline): For , suits - 20 for each bid trick, for , and NT - 30 for each bid trick (40 for first NT trick). If DOUBLED, multiplied by 2, if REDOUBLED - multiplied by 4;

Here is the example of rubber Bridge score:

a) NS (North-South pair) bid 3NT - 9 tricks and this contract completed without any overtrick. 100 points under the line (that means a NS pair completed one game and scoring sheet is divided by another horizontal line);

b) WE (West-East pair) bid 2, which was completed without any overtricks;

c) WE bid 2, which was doubled and redoubled. Contract was completed with one undertrick. That gives NS pair 200 above the line (1 undertrick doubled and redoubled = 200);

d) WE bid 4 contract which was successful, which means 120 points under line. WE pair completed one game and sheet is divided by another line;

e) WE bid 6NT and completed. That is 190 points under the line. This is the second game won by this pair which makes a complete rubber. For this, the pair receives bonus points - 500 for rubber, 750 for successful little slam (WE - vulnerable).

So, WE won the rubber 1620 to 300. But you should notice that winning the rubber does not always mean winning the whole game because the winner is the pair with the most points. All game points appear after the game in a score sheet (red).

Apart from the international scoring there are other systems. Even though those systems are popular only in some countries, many Bridge players use them. In our game, players can switch between them. Here are the descriptions:

CHICAGO

The Chicago system differs from normal rubber Bridge scoring. In rubber Bridge it is impossible to predict how many deals the game will take. The Chicago system always consists of four deals. Bonus for a game is 500 when vulnerable or 300 when not vulnerable. For partial players gain 50 points, there is a special bonus - 50 for every double in a successfully completed contract. There is also the difference in undertrick penalties - if a pair is vulnerable it gets 100 for the first one, 200 for the second and the third and 300 for the next ones. Comparing to the international system, there is also one important thing - vulnerability is not gained after a successful game but it is received by players as follows:

This four-deals scheme can be repeated many times.

IMP's

Also called as Chicago with Russian Scoring.

This system differs from the Chicago one only with calculation of points. It eliminates a lot of luck while playing the game.

In a pack there are some cards, whose value is bigger than others and they are called Honors. Having finished the game both pairs count the number of points they had before the game. Points for Honors are counted as follows:

That means that in a pack there are 40 points. A pair that gets more points finds its theoretical value in following table:

This is the value of Bridge points which a pair should get with the specified number of honor points in hand. It is compared with the real value of the received Bridge points. The difference between those values is transformed to IMP's.

For example if a pair received 50 points more than it was predicted, they get 2 IMP's. If the difference is -170, which means a pair had less than expected they lose 3 IMP's. The rest of rules are exactly the same as in the Chicago system.

RANKING

Ranking określa poziom umiejętności graczy. Im wyższy ranking tym lepszy gracz. Ranking może przyjmować wartości z przedziału 0-10000. Kiedy gracz po raz pierwszy siada do gry otrzymuje ranking 5000. Później ten ranking może rosnąć lub maleć (w zależności od wyników otrzymywanych przez graczy). Obliczany jest na podstawie wzorów wykorzystujących analizę statystyczną i zbudowany jest w oparciu o jeden z przetestowanych modeli symulacyjnych, który dawał najstabilniejsze wyniki dla testowanej grupy graczy. Model ten jest częściowo adaptacyjny, więc może zmieniać się wraz ze zmieniającymi się strategiami graczy. Ze względu na złożoność stworzonego modelu poniżej umieszczona jest jedynie lista reguł wykorzystanych podczas przygotowywania modułu liczenia rankingu: