Wbridge5

This is the convention card used by Wbridge5, a prominent French bridge software.

This is a 2/1 bidding system. Some conventions are popular only in France, but they improve the American bidding structure.

The software evaluates hands with real-time double-dummy analysis, unsuitable to describe in the convention card. Nevertheless, there is big data from Thomas's Bridge Fantasia telling us what to bid.

Estimated tricks

NT

A = 4, K = 2.8, Q = 1.8, J = 1, 10 = 0.4
Estimated tricks = (Combined points - 7) / 2

Suit

A = 4.5, K = 3, Q = 1.5, J = 0.75, 10 = 0.25
- = 3, x = 2, xx = 1
Estimated tricks = (Combined points + 3) / 3

Binky points

Binky points are directly estimated tricks, either in NT or the best suit contract. This is the best additive trick estimator, without knowledge of fit.

Adjustment

At IMPs

Half of the time, the combined hands can make the estimated tricks or more.
Bidding a grand slam needs 13.5 tricks, i.e. 0.5 more.
Bidding a game needs 0.5 less tricks.

Rounding

The resolution of evaluation is 0.5 tricks, so one can upgrade the hand by 0.25 tricks to find slightly more games.

Levels

One-level opening

Opening at IMPs requires 4.00 NT tricks (12.0 points) or 4.50 suit tricks (12.0 points).
Opening at MPs requires 4.25 NT tricks (12.5 points) or 4.75 suit tricks (12.75 points).

Game

3NT requires 8.0 tricks (23.0 points) seen at IMPs, 8.5 tricks (24.0 points) at MPs.
4M requires 9.0 tricks (24.0 points) seen at IMPs, 9.5 tricks (25.5 points) at MPs.
5m requires 10.0 tricks (27.0 points) seen at IMPs, 10.5 tricks (28.5 points) at MPs.

Slam

Small slam requires 12.0 tricks seen, i.e. 30.0 points for 6x, 31 points for 6NT.
Grand slam requires 13.5 tricks seen, i.e. 34.5 points for 7x, 34 points for 7NT.