working notes in strategic reasoning
Game Theory Playground
Learn game theory by running the choices, not by memorizing definitions.
Each simulation reduces a real situation to players, strategies, payoffs, and a question: what changes when one person changes alone?
01
Name the players
02
Move one strategy
03
Read the payoff
Strategic form
Turn conflict into a runnable model
von Neumann
Formalize the rules before arguing about the outcome.
Morgenstern
Treat economics as choices under interdependence.
Nash
Look for a position where no one improves alone.
Schelling
Notice signals, commitment, and focal points.
Shapley / Ostrom
Ask how cooperation, fairness, and commons can survive.
10 playable models
Choose the game, then run the reasoning.
The interaction is deliberately compact: change one variable, watch the mechanism respond, then read why that response matters.
What is Game Theory?
A discipline for situations where your best move depends on someone else's move.
The site treats each concept like a small laboratory: define the players, constrain the moves, compute the consequences, and then ask whether the result is stable, fair, efficient, or fragile.
Payoff
What each participant gains or loses.
Incentive
Why one move becomes tempting.
Stability
Whether anyone wants to deviate alone.
study routes
Short paths into the playground
route 1
Split Rent Fairly
Three roommates rent a $1600 apartment with rooms that feel valuable for different reasons.
route 2
Prisoner’s Dilemma
Two roommates are accused of stealing takeout and must stay silent or betray each other.
route 3
Nash Equilibrium
Two milk tea shops choose where to locate between downtown crowds and suburban calm.
route 4
Vickrey Auction
Three roommates submit sealed bids for the most desirable bedroom.
route 5
Envy-Free Allocation
Ava likes cream, Ben loves chocolate, and Chloe wants fruit.
route 6
Shapley Value
Three teammates produce a $1000 project, but their value depends on who collaborates.
Glossary
payoff
The value a player receives from an outcome.
strategy
A complete action plan for a player.
dominant strategy
A strategy that is best no matter what others do.
equilibrium
A stable strategic pattern where players are best-responding.
surplus
Value received minus price or cost paid.
allocation
An assignment of goods, rooms, tasks, or resources.
coalition
A group of players working together.
stable matching
A matching with no pair who both prefer each other over their assigned partners.