Q-Plus Bridge 15.7

                                                                        by Hans Leber

Q-Plus has been updated to 15.73 in 2023, latest version is from October. Demo link is available below.

Q-Plus Bridge is one of the oldest Bridge Programs. The total development time (since its start in 1990) is now approximately 22.000 hours.

The Creator

Hans Leber is a 58-year old Austrian now living in Munich, Germany. He is the sole creator of Q-plus Bridge, although the project began as a joint hobby for Hans and Gero Scholz. Hans has studied Computer Sciences. He works since 1998 professionally with bridge programs, not only with Q-Plus Bridge but also with several tutorial programs (made in cooperation with several authors), now more than 20 titles.

In WCBC 2019 Q-Plus Bridge won the bronze medal together with WBridge5. Hans Leber is the man on the far right.
In WCBC 2019 Q-Plus Bridge won the bronze medal together with WBridge5. Hans Leber is the man on the far right.

The tutorial programs make up the majority of Hans earnings, but at the other hand, they also consume a lot of time, thus reducing the time available for improvement of the algorithm, which is his favorite activity.

Hans says: "There are two kinds of people writing bridge programs: bridge players who try to program and programmers who try to play bridge. I belong clearly in the second group: I was a total novice at the beginning of the development, and am now an average player."

The Software

Q-plus Bridge is a bridge-playing program that communicates with its users in five different languages: English, German, French, Italian and Danish. Its life began in 1990, when Hans developed it for the "Computer Olympiad of Thinking Games". The program was originally called "Bridge King".

"These early Computer Olympiads were very important," comments Hans. "Without them, I believe Q-plus Bridge would never have been born. In 1992 Bridge King won the Olympiad, although I have to admit that luck was on our side. "Since those early days, Bridge King has metamorphosed into Q-plus Bridge,

The software operates in two quite different ways. The bidding is rule-based: it has rules such as 'with 12 points, you open the bidding'; there are about 30,000 lines of code. In the play, Q-plus Bridge generates hands based on known facts from the bidding and the early play. It then bases its next play on the success of various options on the generated hands. If the analysis of the generated hands does not produce a conclusive result, then general rules are applied. For example, if there is a choice of taking a trick or ducking, and there seems to be not much difference, the program prefers to duck, at least early in the hand.

The number of bidding conventions supported, must be one of the highest of all programs.

One relevant improvement has been that Q-plus Bridge bases decisions on simulations not only during the play, which all programs do. But also during the bidding, which is not unique, but it does use this technique more than other programs).

Hans is optimistic about the future of development of Q-Plus Bridge.

Q-Plus Bridge has competed in the World Computer Bridge Championship since the begining of 1997. It has never won, but been Runner up 4 times, latest in 2011.

Q-Plus Bridge is a commercial program. A demo version is available for download.

The commercial version of Q-Plus Bridge is available at Svenska Bridgef√∂rlaget 

Q-Plus Bridge is available for Windows and Android Devices (limited functions). 

It is not available for Mac, but can be run with a suitable Windows emulator.

Q-Plus Bridge can now also be run in a browser,  demo and the full version.  (new)

List of system and features of Q-Plus Bridge 15.7, released in October 2023. 

Q-Plus Bridge is used as bot on Swan Games.

Q-Plus Bridge attended Christine Gouldens bot championship. in 2023. It did very well and won the Final against  WBridge 5.2.