BidBase: bridge bidding rules in the browser

Rules Conventions Loading the engine and rules (about 1 MB)…

Dealer Vulnerable BidBase bids all four seats. Click a call to see what it means.

BidBase tries these in order and makes the call of the first one the hand fits. Greyed rules are switched off.

Switching a convention changes this page's bidding until the rules or settings are changed.

About

CardShark BidBase is Nelson Ford's bridge bidding program, written in Visual Basic since about 2000. Its knowledge is a database of rules: each names the auction so far, a call, and what the hand needs (points, suit lengths and strength, shape, stoppers, position, vulnerability). For a hand, BidBase tries the auction's rules in order and makes the call of the first rule the hand fits. Conventions can be switched on and off.

This page runs a Rust port of Nelson's engine, compiled to WebAssembly, on his 2026 rules (16,786) or the 2018 SourceForge release (5,465). Nothing is sent anywhere: it all runs in your browser. Where no rule fits, BidBase passes; Nelson's own practice program can also choose a call by double-dummy analysis there, which this page does not do yet.

BidBase is Nelson Ford's work. His site says: "All the databases, text files and programs making up BidBase are free public domain." The port is at github.com/bridge-craftwork/bidbase, with Nelson's programs and rules.