Gomoku for two people sharing one phone, tablet or computer. Black and White take turns placing stones on a 15×15 board, and the first to line up five in a row — across, down or diagonally — wins. Renju restrictions for Black (no double-threes, double-fours or overlines) are on by default, and every forbidden point is marked with a red ✕ before you play it; switch them off and you get plain free-style five in a row. No install, no account — open the page and start.

How to play

1. On the title screen, set Black restrictions (3-3, 4-4, overline) to On or Off. On is the default. The choice is remembered on this device and applies from the next new game.
2. Press Play together. The play screen shows a card for Black and one for White at the top, with the side to move glowing with a lime border, the move count in the middle and a one-line message underneath.
3. Black moves first. With a mouse, hover over an intersection to see a translucent preview stone and click to place it. On a touch screen, tap once and the app shows a translucent stone with a lime ring and the message “Tap again to confirm”. Tap the same point again to place the stone, or tap somewhere else to move the preview there. Tapping an occupied point just says “That point is taken”.
4. The last stone played carries a red dot, so the other player can see at a glance where you went. The buttons below the board are Undo, New game and Resign.
5. When five connect, a lime line is drawn through the five stones and the result overlay appears with a 🏆 winner and the reason (“Black made five in a row”, for example). If all 225 points fill up with no five, it is a 🤝 draw.
6. The overlay also shows Series today — wins, losses and draws counted while this page has been open (a refresh resets it). Choose Play again for the next game, Share result to send the result text and a link through your device’s share sheet or copy it, or Title to go back to the start.

Rules

The board is a 15×15 wooden grid with five star points. Black plays first and the two sides alternate, placing one stone on any empty intersection. Stones never move and are never removed. The first player to connect five of their own stones in a straight line — horizontal, vertical or diagonal — wins.

Restrictions On (default)	Black may not play a double-three, a double-four or an overline. Black wins only with exactly five; White wins with five or more (six and seven count too).
Restrictions Off	No forbidden points. Either side wins with five or more in a row.

• Double-three (3-3) — one stone creates two open threes at once (an open three has both ends free, so it becomes an open four next move).
• Double-four (4-4) — one stone creates two fours at once (a four needs just one more stone to make five).
• Overline — six or more black stones in a line.
• On Black’s turn, every forbidden point is shown with a red ✕ in advance. Tap one and the message explains why, such as “Double three — that makes two open threes”.
• A move that completes five in a row wins even if it also forms a forbidden shape. Five comes first.
• If the board fills up completely, the game is a draw.
• Undo takes back the last move, as many times as you like, until the game is decided.
• Resign changes to “Really resign?” on the first press; press again within 2.5 seconds and the side to move loses.

Tips

• Keep your first few stones near the centre star points. Stones on the edge have fewer directions to grow in.
• Block open threes immediately. Left alone, an open three becomes an open four, and an open four cannot be stopped at both ends.
• Playing White? Use Black’s restrictions against them. If the point Black needs to defend is marked ✕, Black simply cannot go there.
• Playing Black? Aim for a four-three — a four and an open three made with a single stone. Unlike 3-3 and 4-4 it is legal, and it is very hard to answer.
• Before every move, scan for four enemy stones in a line. Start around the red dot on the last stone; that is where most threats appear.
• Lost track of where it went wrong? Before the game is decided, Undo a few moves and try a different line. There is no limit.

FAQ

What is a double-three?

A shape where one black stone creates two open threes at the same time. Each open three turns into an open four with one more stone, and White cannot block both. Because Black already has the advantage of moving first, renju rules forbid this point for Black. In this app the point is marked with a red ✕ on Black’s turn, and tapping it shows “Double three — that makes two open threes”.

Why does White win with six in a row?

Moving first is a real edge in gomoku, so renju rules restrict only Black. White is free to make double-threes, double-fours and overlines, and six or seven in a row count as a win for White. Black wins only with exactly five. Turn the restrictions off and both sides win with five or more.

What changes when the restrictions are off?

There are no forbidden points and no ✕ marks. Black and White both win with five or more in a row — the free-style gomoku most people learned on paper. Change it on the title screen; it takes effect from the next new game.

I tapped the wrong spot on my phone.

A single tap never places a stone on a touch device — it only shows a translucent preview with a lime ring. Tap a different point to move the preview, and tap the same point again to confirm. If a stone still lands in the wrong place, Undo takes it back.

How many times can I undo?

As many as you want; each press takes back one more move. Once the game is decided, Undo is no longer available — start a fresh game with Play again.

Can I play with a friend who is somewhere else?

No. This gomoku is for two people at one device, taking turns. Put the phone between you and pass it back and forth, or sit side by side at a computer and share the mouse.

More games for two

• Reversi · Othello (2 players) — legal moves are shown and passes are automatic.
• Janggi · Korean Chess (2 players) — pick your horse and elephant setup, full rules with check and bikjang.
• Chess (2 players) — castling, en passant, promotion and checkmate all handled for you.
• Alkkagi · Stone Flicking (2 players) — the same go stones, flicked slingshot-style to knock the other side off the board.
• Sudoku — for when your opponent has gone home.