Bridge Simulator

Simulate thousands of hands to analyze contract and leads success rates

The Simulator runs large-scale deal generation and double-dummy analysis to produce statistical insights. It follows a guided 5-step flow.

Contract Simulation - Analyze how often each contract makes, average tricks taken, constraint distributions, and more across thousands of random deals.
Lead Simulation - Evaluate all 13 possible opening leads for a specific contract. Find the best lead based on average tricks given to declarer.

Define hands for each player. You can mix Cards mode and Constraints mode across different players.

Click individual cards from each suit (Spades, Hearts, Diamonds, Clubs) to assign them to the selected player's hand.
Selected cards are highlighted. Click again to deselect. A counter shows how many cards you have selected out of 13.
Cards assigned to one player are no longer available for other players.

Instead of picking exact cards, define rules that generated hands must satisfy. Constraints are organized in sets, each containing four tabs: Shapes, Suits, Honors, and HCP.

A constraint set is a group of rules that a generated hand must satisfy.
Create multiple sets per player using the "+ New Set" button. When multiple sets exist, a hand only needs to match one of them (OR logic).
This lets you describe complex hand profiles - for example, Set 1: "balanced with 15-17 HCP" OR Set 2: "any shape with 20+ HCP".
Each set can be renamed, duplicated, or deleted. The "Active Constraints" summary at the bottom shows your current rules at a glance.

Control the hand distribution shape. Contains four tools:

Choose from hand distributions organized by category: Balanced (4-3-3-3, 4-4-3-2, 5-3-3-2), Semi-balanced (5-4-2-2, 6-3-2-2), Two-suited, Three-suited, and One-suited.
Use the Allowed / Excluded toggle to control how selected shapes are applied.
Allowed mode: only the selected shapes will appear in generated hands.
Excluded mode: the selected shapes are filtered out; all other shapes are allowed.

Set a minimum and maximum number of cards for each suit independently (e.g., 5-7 Spades, 0-2 Hearts).
Each range can be toggled as Required (hands must satisfy it) or Excluded (hands matching it are filtered out).
Click "Add" to activate the range. You can add multiple ranges to the same set.
Useful when predefined shapes are too broad - for example, requiring exactly 5+ spades and 4+ hearts.

Constrain the combined length of two or more suits together.
Select the suits to include (e.g., Spades + Hearts for majors), then set a min and max total.
Example: require that the two major suits total 8-10 cards.

Compare the lengths of two suits using an operator and an offset.
Select the first suit(s), an operator (=, ≥, ≤, >, <), the second suit(s), and an optional offset.
Example: Spades ≥ Hearts + 2, meaning the hand must have at least 2 more spades than hearts.

Define card-level requirements and controls for slam analysis:

Require that the hand holds a certain number of specific cards from a defined pool.
Select one or more suits and one or more card ranks (A, K, Q, J, T, 9-2), then set a min and max count.
Cards within the same suit use OR logic (hand needs any of those cards in that suit). Cards across different suits use AND logic.
Example: require at least 2 of the top 3 spades (A, K, Q of Spades, min 2).

Define first-round and second-round controls per suit - useful for slam-oriented hand generation.
First Round Control: requires the Ace or a void in the selected suit.
Second Round Control: requires the Ace, King, void, or singleton in the selected suit.
Select one or more suits to apply each control type.

Require specific honor cards (Ace, King, Queen, Jack) in each suit.
Click the honor card buttons per suit to toggle them on or off. A counter shows how many honors are required (up to 5).
Example: require the hand to hold the Ace and King of Spades and the Ace of Hearts.

Set a minimum and maximum HCP range for the hand (0-37).
Standard counting: Ace = 4, King = 3, Queen = 2, Jack = 1.
Click "Confirm HCP" to apply the range to the constraint set.
Combine with shape and suit constraints for precise hand types - for example, "balanced with 15-17 HCP".

Pick the declarer: North, East, South, or West.
Select contracts from the full grid - all levels (1-7) across all five strains (Clubs, Diamonds, Hearts, Spades, No Trump). Up to 5 declarer/strain combinations per run.
Choose the contract status: undoubled, doubled, or redoubled.
Set the vulnerability for each side (Non-Vulnerable or Vulnerable).
For Lead Simulation, the contract determines which opening leads are evaluated.

Choose how many hands to simulate: 1000, 5000, 10000, or 20000.
Larger simulations produce more reliable statistics but cost more credits.
Maximum duration is 10 minutes.

Review detailed statistical output including distribution charts, probability tables, and double-dummy results.
For Contract Simulation: see how often the contract makes, average tricks taken, and how constraints are distributed.
For Lead Simulation: compare all 13 opening leads ranked by average tricks given to declarer.

Common questions

Contract Simulation analyzes how often a contract makes across thousands of random deals matching your constraints, showing success rates, average tricks, and statistical distributions. Lead Simulation evaluates all 13 possible opening leads for a specific contract and finds the best lead based on average tricks given to declarer. The hand simulator guide walks through both, and the guide to opening leads covers the principles behind the choice of lead.

See step 2 above for full details on each type.

You can choose between 1000, 5000, 10000, or 20000 hands. Larger simulations produce more reliable statistics but cost more credits.

Simulation Type

Choose the type of simulation you want to run