How to Play

Tic-Tac-Toe 3D keeps the friendly, take-turns spirit of the game you already know and lifts it off the page into a cube. If you can play noughts and crosses on paper, you can play here in seconds — but the extra dimension opens up dozens of new ways to win. This guide walks you through the board, the rules, the controls and how to pick a game that suits your mood.

The board

Instead of a single flat 3×3 grid, the game is played inside a cube made of stacked layers. You choose how big that cube is before the match begins, anywhere from a compact 3×3×3 (three small layers of nine cells) up to a sprawling 10×10×10 . A small cube plays fast and sharp; a large one turns into a slow, tactical battle with hundreds of cells and a huge number of possible lines. If you are new, start at 3×3×3 or 4×4×4 and grow from there.

The goal: complete a line

The aim never changes: be the first player to fill a straight, unbroken line with your own pieces. What changes in three dimensions is how many directions that line can run. On a flat board a line is only ever a row, a column or a diagonal. Inside a cube, a winning line can be any of the following:

• Rows and columns — straight across a single layer, exactly like the classic game.
• Pillars — straight up or down, passing through every layer in the same spot.
• Face diagonals — corner to corner within any flat slice of the cube, whether that slice is horizontal or vertical.
• Space diagonals — the long diagonals that travel through the body of the cube from one corner all the way to the opposite corner, changing row, column and layer at every step.

The length of a winning line matches the board: on a 5×5×5 cube you need five in a row, not three. Those space diagonals are the ones new players miss most often, because they only become visible when you rotate the board and look through it.

Taking a turn

Players alternate turns. On your turn you claim one empty cell by clicking or tapping it, and your piece — a polished sphere of marble or wood — settles into place. Your opponent then does the same, and play continues until someone completes a line or the cube fills up with no line made, which is a draw. There is no capturing and no moving pieces once placed; every turn simply adds one new piece to the board.

Controls

• Place a piece: click or tap an empty cell.
• Rotate the board: drag with the mouse or swipe with a finger to spin the cube and study it from any angle. This is essential — many lines are impossible to judge from a single viewpoint.
• Fullscreen: use the fullscreen button beneath the board for a bigger, distraction-free view.

Everything runs directly in your browser on desktop, laptop, tablet and phone. There is nothing to install and no plugin to enable.

Choosing a board size

Board size is the single biggest lever on how a game feels. A 3×3×3 cube is quick and forgiving, perfect for learning where the lines run. Move up to 5×5×5 and the game rewards planning several moves ahead. At 8×8×8 and above, matches become long, strategic and unforgiving of a single missed threat. Pick the size to match how much time you have and how deep a challenge you want.

Ways to play

• Online multiplayer — face real opponents from around the world and climb the global leaderboard.
• Single player vs. AI — practise against a computer opponent, a great way to get comfortable with three-dimensional lines at your own pace.
• Local two-player — hand one device back and forth and play a friend on the same screen.

Ready to go deeper? Once the rules feel natural, read the strategy guide to learn how strong players create double threats and win the race to the first line. Or just press play and start experimenting — a few games is the fastest way to see the cube the way experienced players do.