Bridge Simulator: Custom Bridge Simulations
Set constraints, generate many deals that fit them, solve each one with double-dummy analysis, and compare actions by expected performance.
A bridge simulation estimates which bid or which opening lead scores best, given what the auction tells you. The bridge simulator deals up to 1000 random hands that fit your constraints, solves each deal double dummy, and ranks every choice by average score, making percentage or defeat rate.
Constraints
Express what you know: HCP ranges, suit lengths, shapes, and auction context.
Generate many worlds
BridgeDummy generates many possible deals consistent with your constraints to reduce single-deal noise.
Compare decisions
Evaluate candidate actions (bids/leads) by expected outcome across generated deals using double-dummy analysis.
Watch it in action
Four short videos: from your first simulation to conditional contracts.
Read the full written guide1. Getting started: bidding simulations
Enter your hand, constrain the unseen hands, pick up to 4 bids and compare average score, IMPs, making percentage and matchpoints.
2. Lead simulations
Pick the contract you defend and see which opening lead wins at matchpoints vs IMPs, with sample deals to inspect.
3. Hand constraints
Shape flags, key cards, controls, stoppers and OR-alternatives: describe exactly what the auction told you.
4. Conditional contracts and advanced options
Build if-then bids like 4 spades if partner has 3-card support, else 3NT. Plus templates and saved simulations.
FAQ
- What is a bridge simulator?
- A bridge simulator is a program that deals many random bridge hands that match what you know about the other three players, then scores each possible action on all of them. BridgeDummy plays every simulated deal double dummy, so each bid or lead gets its result with perfect play and all four hands known. The average shows which choice scores best under that assumption, and real play can differ.
- What are custom bridge simulations?
- Custom bridge simulations let you define an auction and constraints (shape, points, suit lengths) and then generate many deals to evaluate decisions using double-dummy analysis.
- Can I simulate bridge deals with constraints?
- Yes. BridgeDummy supports auction-based deal simulation and constraint-driven deal generation for advanced analysis and practice.
- How many deals does a bridge simulation use?
- Each BridgeDummy run aims for up to 1000 deals (650 when the contracts span 3 strains, 500 for 4 and 400 for 5) and can stop early, at 300 deals or more, once the results are precise enough. If fewer than 200 deals match your constraints, the results show a low sample warning, so widen the ranges for a more reliable answer. A run with 5 or more deals still costs its 15 diamonds.
- Is this a Monte Carlo simulation?
- BridgeDummy generates many deals consistent with your constraints and evaluates outcomes across them. In practice it behaves like Monte Carlo simulation for bridge decision analysis.