The probabilistic problem of the contract bridge player

During a game of bridge, each player starts by knowing only her own hand but, as the game progresses, she learns progressively more information about the hands of other players. This information is always partial such as `player north has at least 5 spades and 12 honor points' or `player east has the ten of spades which he just played'.

When she is supposed to bid or play she relies on a guess about the cards other players might likely hold.

The probability calculator is an online program where you may enter, at any stage in the game, all information you have and it computes (based on this principle) probabilities of cards and statistics (such as honor point ranges) about all hands.

It is unlikely you would do this during a game. However, it is particularly useful when you try to analyse a critical step during a previous game and the calculator will reveal what it should have been reasonable for you to guess about the other players' hands.

Potential uses of the calculator include:

analysis of critical stages during a game and settlement of disputes on what would have been predictable at a certain stage;
training of the ability to predict cards in other people's hands by providing a calculated feedback;
evaluation of the ability of bidding systems to communicate relevant information of a team's cards while reducing disclosure of information to the opponents;
a method to augment published comments and analyses with probabilistic calculations by using the URL schema to specify player problems.