Sim is a compact and satisfying strategy game that rewards clear thinking and forward planning. If you’re curious about how to play Sim game, you’ll be pleased to know that the rules are easy to grasp in just a few minutes, while the gameplay provides enough complexity to keep players entertained for many sessions. Just grab a pencil, some paper, and find a willing opponent. No screens, no batteries, no complex setup. Simply geometric reasoning between two participants.
The game, created by Gustavus Simmons in 1969, has become a cherished classic in puzzle and game theory. It fits well within the realm of pencil-and-paper games, like noughts and crosses and dots and boxes, yet provides a unique advantage — a mathematical guarantee inherent in its structure. To play Sim effectively, you must understand this key point: a draw is mathematically impossible in Sim. There must be a winner each time.
Game Setup
Before playing the Sim game, start by drawing the board. Start by placing six dots in a perfect hexagon shape on a blank sheet of paper. Label the points or arrange them evenly in a circle. The size is not important, as long as all six points are visible and approximately equidistant. This hexagonal setup of six vertices constitutes the complete playing area for Sim.
Each of the six dots stands for a vertex, and the game involves drawing lines between these vertices. With six vertices, there are fifteen possible connections between them — each dot can connect to every other dot. These fifteen edges create a complete graph known as K₆, and its properties contribute to the game’s fairness and intrigue. No need to pre-draw lines; they will be added one at a time as the game unfolds.
The Fundamental Guidelines
Playing the Sim game is easy once the board is set up. Two players alternate turns, each assigned a colour — typically red and blue, but any two contrasting colours of pen or pencil can be used. During each turn, a player connects two unconnected dots with a single line. Each turn requires just one action: drawing a line between two unconnected vertices.
The player who must complete a triangle of their own colour loses the game. This is the main rule for playing the Sim game, and everything else follows from it. A triangle here refers to three dots interconnected by lines of the same colour — a closed loop of three edges belonging to a single player. The player whose colour forms a triangle on the board is declared the loser immediately.
Observe that the losing condition is defined by completing a triangle, rather than intentionally creating one. This is important as the game frequently puts players in tough situations where each possible move threatens to complete a triangle. The strategic challenge is to prolong this outcome while creating scenarios where your opponent has no safe moves remaining.
Reasons a draw cannot occur.
One of the most notable features of playing a Sim game — and what distinguishes it from most pencil-and-paper games — is its mathematical certainty. A draw is not possible. This is a theorem established by Ramsey theory, a field of combinatorics, rather than a convention-based rule. In any two-colouring of the edges of K₆, at least one monochromatic triangle is guaranteed to exist. Once all fifteen lines are drawn between the six dots using just two colours, at least one triangle of the same colour will definitely appear. The game must have a winner to conclude.
This knowledge informs tactical gameplay in Sim games. Both players are engaged in a defensive struggle, not competing for points, but strategising to ensure the eventual same-colour triangle goes to their opponent. This creates an unusual tension for Sim. Unlike games focused on achievement, Sim challenges you to avoid certain actions, creating a refreshing shift in mindset with each playthrough.
Fundamental Approach
With the rules established, it’s important to think about the strategy for playing the Sim game effectively. Beginners tend to concentrate solely on evading their own triangles, neglecting the positions they set up for their opponent. Strong players think several moves ahead, anticipating dangerous traps that may arise.
A key principle for playing Sim is to closely observe the degree of each vertex. The degree of a vertex refers to the number of lines of a specific colour that connect to it. If a coloured edge connects to a vertex already linked to two other edges of the same colour, you may close a triangle with your next move at that vertex. Monitoring this count for each vertex on the board aids in pinpointing which areas are turning hazardous.
One effective strategy in playing the Sim game is to distribute your lines across various areas of the board early, instead of grouping multiple connections around a limited number of dots. Focus results in triangles. Distributing your edges evenly keeps options open and lowers the risk of getting boxed in later in the game, when safe moves are limited.
The middle and end game.
As the board fills up, the gameplay of the Sim game shifts significantly. Early play is exploratory, as both players set lines across the hexagon. As the middle stages approach, around eight to twelve lines in, the pressure starts to increase. Certain vertices will have multiple coloured edges, and the number of genuinely safe moves begins to decrease.
This is where true strategic depth in playing the Sim game becomes apparent. A skilled player aims to create a forcing sequence — a series of moves that gradually limits the opponent’s choices until no safe options remain. The opponent must then complete a triangle of their own colour, no matter which edge they select, and the game concludes.
In the final stages, both players often have very few safe moves available. Counting carefully, tracking edges by colour, and visualising potential triangles before making a move are essential skills. Players who quickly grasp the board geometry will see significant improvements in their results.
Advice for Beginners
For beginners exploring Sim games, a few practical tips can accelerate the learning process. Redraw the hexagon larger to ensure clarity inside; cramped spaces cause misreads and disputes over triangles. Secondly, choose colours that strongly contrast; light pencil on dark ink can lead to confusion during the game. After each game, review the moves to pinpoint when one player’s position became unavoidable. This analysis is the quickest route to enhancement.
Accepting early losses as a natural part of the process is beneficial when learning to play a Sim game. The game’s strategic layer reveals itself only after you endure the discomfort of being slowly cornered. When you experience that internal pressure, you learn how to exert it on others.
Reasons for Sim’s Longevity
Sim persists as it accomplishes a unique feat in abstract games: it is both demonstrably fair and truly unexpected. Every game concludes with a clear outcome, but the journey to that outcome varies each time. The fifteen edges of the hexagonal board provide ample variety for ongoing play without the risk of repetition.
Playing the Sim game provides insight into combinatorics and graph theory, offering an educational experience while being entertaining. Educators have utilised it to foster mathematical thinking; puzzle fans have employed it to enhance spatial reasoning; and casual players have relished it as a compact, aesthetically pleasing game that can be played on a serviette.
Whether you’re a first-time player or coming back after years, the rules for playing the Sim game stay the same: draw the hexagon, take turns adding coloured edges, avoid completing a triangle in your own colour, and plan at least two moves ahead. Master the fundamentals, and you’ll discover Sim to be one of the most rewarding pencil-and-paper games ever created.