Bridge Conventions
- Presents an extensive list of explanations and definitions.
- http://www.pattayabridge.com/convindex_main.htm

Zar Points
- Aggressive hand evaluation and bidding based on distribution, controls, and hcp. Presents the Zar Bid Machine.
- http://www.zarpoints.com

Inquiry 2/1 GF
- Online book prensenting the author's variation of this popular north american system.
- http://inquiry2over1.blogspot.com/

Coyot's 2/1 Game Force
- Detailed presentation of this american system.
- http://web.pinknet.cz/~coyot/sa21gf/sa21gf_en.php

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.
- http://www.kentfeiler.com/bridge/home/bridge.htm

Bridge Files
- Provides overview of different systems, a list of conventions and information about the game. Free registration required.
- http://www.bridgefiles.net/

Bridge Guys
- Lists and defines a large number of systems and conventions.
- http://www.bridgeguys.com/

Caliper
- Bidding system from Norway based on a Big Diamond relay sequence.
- http://home.no.net/foevsted/

The Chilli Bidding System
- Gives priority to simplicity and universality of rules.
- http://chillibidding.org/

REGRESsion
- Modification of the bidding system Regres, based on frequent openings with weak hands and opening passes with strong hands.
- http://members.ams.chello.nl/a.denbroeder4/index.html

Bidding Order Shows Strength (BOSS)
- Describes a system where priority is given to the strenght of the partnership hands.
- http://www.jhardie.pwp.blueyonder.co.uk/boss.htm

Polish Standard 2000
- Description of the Polish Club bidding system, with different variants.
- http://www.wj2000.front.ru/

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.
- http://public.aci.on.ca/~zpetkov/

Bidding by Design
- Proposes articles on bidding system theory and offers examples for download. Free system design software available for download.
- http://www.xs4all.nl/~jisbert/

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 su
- http://www.bridgeworld.com/default.asp?d=bw_standard&f=bwstandardmainpage.html

Precision Two-over-One
- Presents an overview of a system mixing a strong club with standard methods.
- http://www.p21.150m.com/

An Unassuming Club
- Presentation of a variant of the Polish Club system.
- http://www.bridge.hotmail.ru/file/Red/auc/club.html

The Diamond Major
- Forcing club, 5-card major, medium notrump system.
- http://www.bridgeclublive.com/Include/Diamond.htm

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.
- http://www.biddingquest.com/

Brazilian Bridge
- Presentation of the Carioca Club and other conventions.
- http://sites.uol.com.br/webridge/english/

Contract Bridge Culbertson System
- Contract bridge bidding, as developed by Culbertson. Culbertson's survey of good playing techniques is also included.
- http://www.stjost.si/bridge/

Precision Bidding System
- Detailed description of the Precision Bidding System (strong 1 club opening, with 16+ points), as modified by one partnership.
- http://acp.atlanta.ga.us/wang/bridge/gdum111.htm

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.
- http://web.inter.nl.net/hcc/M.A.F/

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).
- http://www.mclink.it/personal/MC6246/BlueTeamClub/sistema.htm

Conventions
- Survey of a large number of commonly used bridge bidding conventions and bidding systems.
- http://www.bridgeguys.com/conventions.html

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).
- http://home.no.net/raptor/

Bidding Guide
- Introduction to standard American bidding.
- http://www.math.cornell.edu/~belk/

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.
- http://www.annam.co.uk/sayc.htm