Bridge Bidding Guide - Look-up tables for bridge bidding, with the most common conventions used in Standard American bidding, by Richard Pavlicek.

Aggressive Bidding Foundation - Proposes an approach based on a math model over computer analysis. Provides famous pairs systems, an exposition of the theory and a bidding machine.
Meta Description: [ Aggressive bidding foundation, based on a math model over computer analysis of more than a million deals - considered the most accurate bidding platform ever created, proven to perform times better than the most popular Goren and Bergen methods and their variations. ]

An Unassuming Club - A bidding system invented by Donald A. Varvel of Mountain View, CA, USA. It is based on an ambiguous 1 club opening, associated with 5-card majors, weak no trumps, and weak 2s.

An Unassuming Club - Presentation of a variant of the Polish Club system.

B-M Precision - Detailed presentation of a variation of the system.

Bidding by Design - Proposes articles on bidding system theory and offers examples for download. Free system design software available for download.

Bidding Guide - Introduction to standard American bidding.

Bidding Order Shows Strength (BOSS) - Describes a system where priority is given to the strenght of the partnership hands.

404 Bidding Quest - Practice bidding on prepared deals with scores. Compare and check how other pairs have bid same boards. Try bidding competition with anonymous partner.

Brazilian Bridge - Presention of the Carioca Club and other conventions, links.

404 Bridge Bidding Systems and Conventions - Thorough listing of bridge bidding systems and conventions, particularly those used in North America.

Bridge Conventions - Provides an encyclopaedia of conventions, systems and treatments.
Meta Description: [ A compendium of over 250 bridge bidding conventions, systems, signals and discards. ]

404 Bridge Files - Provides overview of different systems, a list of conventions and information about the game. Free registration required.

404 Bridge Guys - Lists and defines a large number of systems and conventions.

Bridge is it - Concerned with bridge bidding systems, especially CLONE, based on a forcing weak/strong 1 club opening. Also features links to other bridge resources, particularly on bidding systems. Bilingual site (English/Norwegian).

Bridge World Standard - Description of a bridge bidding system based on the preferences of leading players, and aimed at the needs of occasional partnerships. Some characteristics: 5-card major opening, strong no-trump, artificial strong two-club opening, weak 2s in the other suits, and inverted minors.
Meta Description: [ The Bridge World Magazine, Bridge Articles, Learn Bridge, Practice Bridge, Play Bridge, bridge resources. ]

Caliper - Bidding system from Norway based on a Big Diamond relay sequence.
Meta Description: [ Bridge bidding system based upon Magic Diamond and Symmetric Relays. Intermediate 1 Club - Strong 1 Diamond - Light openings. ]

Colonial Acol and LISA - Presentation of two bidding systems, one a US adaptation of the British Acol system, the other a modification of Standard American.

Contract Bridge Culbertson System - Contract bridge bidding, as developed by Culbertson. Culbertson's survey of good playing techniques is also included.

404 Conventions - Survey of a large number of commonly used bridge bidding conventions and bidding systems.

Coyot's 2/1 Game Force - Detailed presentation of this american system.

Inquiry 2/1 GF - Online book prensenting the author's variation of this popular north american system.

404 Josh's Bridge Pages - A Simple System - Description of a simple bridge-bidding system played by some British players, based on weak NT and four-card major openings.

M.A.F. - The Ultimate Bridge Bidding System - A scientific bidding system from the Netherlands (5-card majors and different two-suiter openings). Bilingual site gives information in English and Dutch.

Pekiner, YAlçin - Proposes a collection of articles, tests and free software. English and Turkish.
Meta Description: [ Learn or improve your bridge by numerous articles, tests and free software. Bedava programlarla bri grenin veya bricinizi gelistirin. ]

Polish Standard 2000 - Description of the Polish Club bidding system, with different variants.

Precision Bidding System - Detailed description of the Precision Bidding System (strong 1 club opening, with 16+ points), as modified by one partnership.

Precision Two-over-One - Presents an overview of a system mixing a strong club with standard methods.

REGRESsion - Modification of the bidding system Regres, based on frequent openings with weak hands and opening passes with strong hands.
Meta Description: [ A bridge bidding system, based on the weak opening system Regres, but with many modifications ]

SA-YC Simplified - This bidding system is a simplified version (as played on OKBridge) of the Standard Yellow Card (SA-YC) system of the ACBL (American Contract Bridge League). Its essential features include the strong no-trump, 5-card major and weak 2 openings.
Meta Description: [ SAYC (Standard American Yellow Card) and 2/1 are probably the most widely used bidding system when playing bridge online. Find simplified information on the SAYC and 2/1 bidding systems and optional conventions used on OKbridge. ]

The Blue Team Club System - Description of a complex bidding system invented in Italy. A major part of the information is in downloadable files only. Bilingual site (Italian/English).

The Chilli Bidding System - Gives priority to simplicity and universality of rules.
Meta Description: [ Chilli is an unusual bridge bidding system that places simplicity and universality of rules as its highest priority. This small, powerful and unusual approach to bidding was developed by Alan Williams, with help from his partners Michael Booker, Geoff Lacey and Mike Wenble. ]

The Diamond Major - Forcing club, 5-card major, medium notrump system.
Meta Description: [ Bridge Player LIVE! - The Friendliest Internet On Line Bridge Club for Contract and Rubber Bridge 24 hours a day! Free guest account ]