Solving Otrio

Edit from the future: I was super humbled when the creator of the game, Brady, instructed me that I had been playing the game incorrectly. Therefore all of what is below is based off of an improper ruleset to the game. The real rules make the game much deeper (and less obviously solvable)


I was gifted a game from the Marbles Brain Store for holidays this year called Otrio.



Its based off of Tic-Tac-Toe where a row of three O’s that are the same or ascending/descending in size or three concentric O’s gives victory. Below are some examples of victories:

Its unfortunately also based on a easily solved game, tick-tac-toe. After about ten minutes we determined that player one cannot lose if they play correctly. Here the solutions:

Player 2 plays in a middle edge:


Player 2 plays concentrically:


Player 2 plays in a corner:



12 thoughts on “Solving Otrio

  1. Hello there! As the inventor of Otrio i came across your post. We also figured out that w/ 2 players and using only 2 sets the first person can always win quickly. That’s why we chose to make the rules for a 2 player game use all 4 sets, w/ each player using 2 sets across from each other (not adjacent). We found that this eliminated the first player advantage and made for much better gameplay (tho i personally like the 4 person game the best). Hope you enjoy the game and thanks for playing!


      • You’re actually one of the top results for Otrio right now, so it might be worth it to put an update at the top of the post itself about your error.

        But like Brady said, it’s best with 4 people because you play without any ‘table talk’ addressing strategy or what moves are able to win, so when you play with a novice or younger kid, the game is actually more exciting because you’re not sure whether you ought to block a win for a person following them or advance yourself, but risk them giving a win to someone else.

        If you play with four experienced people, you’ll want to make the turn order go something other than clockwise/counter clockwise because it’s harder to keep track of who to block.

      • Absolutely! I totally had something written and then got distracted trying to write an AI for the game hah

        I do like that idea a lot though. Even not excluding yourself could be fun

  2. So true! I have been playing with my son, one on one, only one color each, and the first player ALWAYS wins. I thought for sure there must be some genius way to overcome this, but I have yet to find one.

    • OK, I figured out that the third color represents all the positions the player can use to win. But it would have been better if you wrote that instead of only having the gifs… It’s 2 am here, and I don’t want to bother my mind with that kind of complicated reasoning… 😉

  3. This is why they put in the “no middle” optional rule for if the first player keeps winning. After hours of playing me and my dad have found out a way to win 1v1 without the middle. The first player needs to put a big ring in the corner. If the player moves anywhere besides a small dot inside your big ring, is going to be an easy win, but if they do you can still win. First I am going to explain what to do if they do not put a small dot in your big ring. If they move somewhere else, all you need to do is put another big ring in corner that is not the corner diagonal from your first big piece. Out of the 2 corners that aren’t diagonal to your ring, you should choose the corner farthest from the piece that your opponent played. Once you put the big circle in the other corner your opponent will be forced to place a big circle imbeteeen your 2 circles. Your next step is to place a medium circle imbetween the 2 big circles you placed. All you have to do is place a small piece in one of your big circles to win, and unless your opponent cheats and blocks you with 2 pieces at once, you have Won! Now let’s wipe the board. Here is what to do if your opponent placed a small dot in your big ring for their first move. All you have to do is place a small dot in any other corner besides the one diagonal to your big ring. This will force your opponent to put a medium piece imbetween your 2 pieces. All you have to do now is place a big ring in the same corner that you just put the small dot piece in. Yet again, you can win in 2 different places. These 2 places are 1# Three pieces in the corner where you placed your 2 pieces already, and 2# Three big circles in a row. So unless your opponent cheats again and blocks both your opportunities at once, you have won, and learned the way how to beat otrio whenever you go first, in a scenario where the middle area is not allowed. Something to advise is that this strategy is beatable if the middle is allowed. If your opponent puts a medium piece in the middle after you place your big piece in the corner, the strategy is bypassed and you will most likely loose if the opponent plays their cards right. And finally, just like all strategies in otrio, if you start with a small piece in the corner, the strategy will still be a garenteed win. All you have to do is put down a small piece every time I said to put down a big piece and on the other hand, put down a big piece every time I said to put down a small piece(still without the middle)

  4. I might be tire but there are two things I can’t understand :
    1. what is the difference between “Player 2 plays in a middle edge” and “Player 2 plays concentrically”
    2. How do the first case win ? I don’t see why the big circle on the bottom would be a win… It would make blue/red/blue big circle which is not a win isn’t it ?

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