How To Play Sim (AKA The Pencil Game) With Your Kiddos

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How To Play Sim
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Nothing beats old-fashioned pencil and paper games when it comes to busting boredom! Sure, we can always turn to our phones and Netflix to distract ourselves, but let’s be honest — even that gets dry after a while. Playing pen and paper games is a great way to sharpen your mind while having some fun. It can also be an enjoyable and effective way to spend time when you’re waiting in the dentist’s office, on vacation with the fam, or just hanging out with the kiddos. They can even serve as a creative way to further engage and connect with your partner. And best of all? Paper games are free and simple. All you need is a pen or pencil and paper to play with! Most of us know the classic kids’ paper games like Tic Tac Toe and Hangman, right? However, we’re here to talk about the Sim game.

A fantastic thinking game to check out, Sim (AKA the “pencil game”) is particularly appealing if you like games that blend math and geometry with a competitive twist. If you’re curious about how to play the popular Sim pencil game, read on for our tips to help get you started.

What is the Sim game?

The Sim game was invented in 1969 by Gustavus Simmons, a cryptographer who first shared it with the world in the Journal of Recreational Mathematics. Simmons modeled the game after graph theory. Need a quick refresher on that principle? In mathematics, graph theory is the study of the relationships between lines and points (which we know as graphs). In other words, get ready to make some graphs!

The game includes two players represented by two different colors. On a sheet of paper, both players will work with six dots arranged in a hexagon. Players will alternately draw a line between the two dots. The first player to draw a triangle of their color between three dots loses. Players can only use 15 moves at the maximum, and the game cannot end in a tie. Only winners and losers here, folks!

How do you play Sim?

How to play Sim is pretty straightforward. Here’s what you need.

What You Need:

  • Paper
  • Two differently colored pens or pencils
  • Two players


Force your opponent to complete a triangle in his or her color.

How to Play:

  • Place six dots on the paper in a hexagonal arrangement. The dots are vertices — which is plural for vertex, referring to the corners where edges meet. Instead of using a blank piece of paper, you can also pre-draw possible lines using a pencil. That way, players can trace over the pre-drawn lines in their respective colors (a solid option for younger kids). However, all lines must always begin and end on the vertices.
  • Decide who goes first.
  • The first player draws a straight line between any two vertices in their color.
  • The second player draws a straight line between any two vertices in their color.
  • Take turns alternately in this fashion until one player completes a triangle in which all three sides are in their color. Alas, that person loses the game.

How do you win the Sim game?

The Sim game is a game based on strategy and math that is rooted in Ramsey’s Theory. At least according to avid Sim players, Ramsey’s theory applies to Sim gameplay. So if you can familiarize yourself with this theory, you’ll increase your odds of winning the Sim game.

There is also some mathematics literature on how the second player can strategize to win the game. Apparently, there’s a so-called perfect playing program for the second player you can find on various Sim game websites. It’s very math-y, but if that floats your boat and you’re keen to best your opponent, you can equip yourself with enough info to win at Sim. And probably dazzle your friends with your math skills at the same time.

When playing the Sim game, avoid rushing to make a box. Many players do this, but more experienced competitors try to trap and double-cross their opponents. This is when you sneakily make several short chains of boxes for your competitor. It forces them to make a long chain for you during their turn and is a sure-fire way to win!

Where can you play the Sim game online?

Need new opponents to challenge? There is a fun website where you can sharpen your skills online here.

What are the benefits of the Sim game?

This game is not only a fun paper game for little ones, but it’s a great way to teach them about shapes and stimulate their spatial reasoning and logical deduction skills. Play the game with your kiddo and ask them how many lines they think they can draw before creating a triangle. Have them guess, and then try it out. Then ask them how many lines can they draw between six points? The Sim game is a great way to begin learning what geometric shapes look like.

What is the story of Charlie Charlie?

If you love the pencil game, you’ll love Charlie Charlie. It’s like messing around with an ouija board but using pencils. This is a traditional Mexican game that requires six pencils and two people. Each person should line the box with three pencils. The open end of the box should face the person asking the question. To begin the game both players must say “Charlie, Charlie, can we play?” If the pencils move inward or up, the answer’s yes. If they move outward or down, it’s a no. If one side goes one way and the other side goes a different way, it means the question can’t be answered at the moment.

Where can I play the Sim game online?

Almost every game can be played digitally in this day and age. So, if you’re on your phone, no where near a pen and pencil, and in the mood to play the Sim game, here are several sites you can play the game for free.

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