From tic-tac-toe to gomoku: winning when the board keeps growing

Why your 3×3 habits stop working at 5×5

Both tic-tac-toe games on crokocat grow as you beat them. Tic Tac Battle and Tic Tac Toe Classic start on the familiar 3×3 grid needing three in a row, then hand you 5×5 where you need four, then 7×7 and 9×9 where you need five — the same family of rules as gomoku, the pen-and-paper classic people have been sharpening for centuries. The computer opponent gets stronger at every step.

The jump feels sharp because 3×3 is a solved memory test. Take the centre, watch for the double-corner fork, and two decent players draw forever. A 9×9 board has eighty-one squares, and no memorised opening survives contact with that much space.

What replaces memorisation is a habit: before each move, count how many ways your shape can still reach five, and how many ways theirs can. The player with more live routes is the one who eventually gets a free double, and the player scattering stones into empty space has none at all.

The open three is a loaded gun

A three with empty squares on both ends is the single most important shape in five-in-a-row. If it survives one turn it becomes a four with two open ends, and a four open at both ends cannot be stopped — one block leaves the other side free. That is why an open three forces an immediate answer: the opponent must either block an end or make a bigger threat of their own.

This cuts both ways, and the defensive half matters more than beginners expect. Never let the computer keep an open three. The moment it appears, blocking it is almost always the correct move, even if it means abandoning a line you were enjoying. Tempo in these games belongs to whoever is asking questions, and an unanswered open three hands the tempo over permanently.

A three that is already walled on one side is a much weaker thing. It can still grow into a four, but a four with only one open end is answered by a single block and dies there. Learning to tell the two apart at a glance is most of the improvement that separates a beginner from someone who wins the 9×9 board.

Double threats: the only reliable way to win

Since one threat always gets blocked, the winning move is the one that makes two at once. In practice that means placing a stone that sits inside two different lines — a horizontal and a diagonal, say — where each line becomes an open three. Your opponent can block one. The other becomes a four the following move and the board is over.

Building one takes preparation, because the double has to arrive as a surprise. Stones placed two or three squares apart along a diagonal look harmless while there is a gap in the middle; filling that gap later is exactly the kind of quiet move that suddenly points in two directions. Broken shapes with a hole in them are worth more than tidy solid rows, precisely because they read as less urgent.

The corollary is defensive. When you are blocking, do not only ask whether their new stone extends a line — ask whether it touches two. A stone that could become the pivot of a fork should be met before the fork exists, because once both threats are on the board there is no move that answers them.

Play near your own stones, and block on the open side

Scattered singles do nothing on a 9×9 board. A stone alone in a corner contributes to no line that anyone will finish, and it costs you the tempo you needed for a real shape. Keep your stones in contact with each other — adjacent or a square apart — so that every new move adds to something. Space is huge, but useful space is only the neighbourhood you already occupy.

When you defend, the side you block on is a real decision. If the opponent's line has three empty squares to the left and one to the right, blocking the cramped side accomplishes almost nothing: they extend the other way and keep the shape alive. Block where they have more room to run, and the line runs out of board on its own.

The edges help you for the same reason. A shape pressed against the rim has fewer directions to grow, so pushing the opponent outward while keeping your own stones toward the middle is a slow, dependable advantage.

Reading the HP bars in Tic Tac Battle

Tic Tac Battle wraps these rules in a fighting-game shell. Before each board you get a VS screen — your chosen emoji fighter on the left, a random challenger on the right, a Fight! button between them — and once play starts, two HP bars swing with every move. The fighter closer to losing bleeds toward red.

Treat the bars as instrumentation, not decoration. They are a live read of the threats on the board: as either side lines up marks toward a win, the other fighter's health drops. When your own bar dips into orange, the computer has an open threat that needs blocking on this move, not the next one. It is the same information a strong player would read off the stones, shown in a form you can catch in half a second on a crowded 9×9 grid.

That makes the game a decent training aid. Make a move, watch which way the bars swing, and you get immediate feedback on whether what you just built actually threatened anything.

Working up through the boards

In Tic Tac Battle, every board you win unlocks a new face for your roster, saved on your device. You start with a single fighter and earn the rest one win at a time, choosing who steps into the ring before every battle — so the progression through 3×3, 5×5, 7×7 and 9×9 doubles as a collection.

Tic Tac Toe Classic tracks the same climb differently. You play X against the computer's O, wins bank points scaled to the level, and a loss resets your streak to zero and replays the same board. First move alternates every round, so neither side keeps the opening advantage — worth remembering, because going second means your early moves should answer rather than build.

If you are stuck on the last board, the fix is usually not a cleverer opening. It is patience: stop chasing an immediate five, spend a few moves building two shapes that share a square, and let the computer block the one you did not need.

Play free in your browser

Both games run on crokocat with no download and no sign-up, on desktop, phone or tablet. In Tic Tac Battle you tap a face on the VS screen to pick your fighter, then tap an empty cell to place it; Tic Tac Toe Classic is a click or tap into any empty cell. Boards scale to fit a phone screen.

The two are worth playing side by side: Tic Tac Toe Classic is the cleaner testing ground for gomoku shapes, while Tic Tac Battle gives you the HP read on every move and a face to unlock at the end of each board. Both were built for crokocat in 2026.

Frequently asked questions

Play it here

• Tic Tac Battle — Pick a fighter, drain their HP
• Tic Tac Toe Classic — Outsmart the computer