How to Play Y

By Jaques of London · Est. 1795 · Updated 2026-08-17

Y is a two-player abstract strategy game played on a triangular grid of hexagonal cells. Each player claims cells one at a time, and the sole objective is to build a chain of connected stones that reaches every side of the triangle at once. The rules fit on a single sentence, yet the game repays serious study.

Players love Y for its elegant symmetry: unlike many connection games, there is only one winning condition and it applies equally to both players, so there is no asymmetric advantage to the goal structure. It is typically played on a physical board with coloured stones or counters, or on paper using a printed hex grid.

A little history

Y was devised in the early 1950s. Its origins are linked to the mathematician and game designer Craige Schensted, later known as Ea Ea, who developed it alongside Claude Shannon's contemporaneous interest in connection games. The game was described and named in publications from that period, with the name referring to the three-way connection requirement. Beyond that, much of the early dissemination history is thin and should be taken as traditional rather than fully documented.

Setting up

1. Place the board between the two players so each can see all three sides clearly.
2. Decide which player takes which colour. A swap rule (pie rule) is strongly recommended: after the first stone is placed, the second player may choose to swap colours instead of placing.
3. Determine who places the first stone, by agreement or by lot.
4. Confirm the board size being used, as 19-per-side is standard but smaller boards (13 or 15 per side) are common for beginners.

How to play

1. Players alternate turns throughout the game; there are no passes.
2. On your turn, place one stone of your colour on any empty cell on the board.
3. A stone placed in a corner cell touches two sides simultaneously; this is permitted and counts for both.
4. Once placed, stones are never moved or removed.
5. Two stones of the same colour are connected if they occupy cells that share an edge (each interior hex has six neighbours; edge and corner cells have fewer).
6. A group is any set of same-colour stones all linked by such connections.
7. The game ends immediately when one player completes a group that touches all three sides of the triangle. That player wins.
8. If the swap (pie) rule is in use: after the first player places their opening stone, the second player may either place normally or declare a swap, taking that stone as their own and giving the first player the opposite colour. Play then continues as normal from the second player's (now first player's) next turn.

Winning and scoring

The winner is the first player to form a single connected group of their own stones that simultaneously touches all three sides of the board. Touching a side means having at least one stone on a cell that borders that side. A corner cell borders two sides, but the winning group must still touch all three sides, not merely two. Because the board fills completely before a draw is possible and exactly one player must eventually win, Y has no draw condition.

The fine points

Corner cells are the most common source of dispute. A stone in a corner touches two sides at once, which is fully legal and beneficial, but a group anchored only at corners still needs to reach the third side independently. Clarify this before play begins. A group that runs along an entire edge satisfies only that one side unless it also connects back to reach both remaining sides.

The swap rule is considered essential for balanced play at all levels, because the first player has a provable theoretical advantage on an empty board (a winning strategy exists for the first player without swap, by strategy stealing). When swap is in force, the first player is incentivised to place a moderate opening stone rather than the strongest possible one. If a dispute arises about whether a swap was declared in time, the standard ruling is that the swap must be declared before the second player touches any stone to place it.

How to win more often

• Aim for the centre of the board early. Stones near the centre have the most connections available and contribute to paths toward all three sides.
• Think in terms of groups, not individual stones. Before placing, ask which of your existing groups the new stone joins or extends.
• Watch your opponent's groups as carefully as your own. A threat that touches two sides already is urgent; block it rather than extending your own position.
• Corner cells are high value because they touch two sides for free, but they anchor paths only in two directions. Do not over-rely on corners at the expense of central connectivity.
• On a 19-per-side board, try to visualise a rough path from each side to the others before committing stones. Spreading stones with no connecting plan wastes moves.

Variations

Smaller board (13 per side)

Reducing the board to 13 cells per side gives 91 cells total and produces a noticeably shorter, sharper game. This is the recommended starting size for new players and for teaching children, as the connection requirements are easier to visualise and games resolve in under 15 minutes.

No swap rule

Some players prefer to omit the swap rule entirely, accepting that the first player holds a structural advantage. This simplifies the opening but is not recommended for competitive play or between players of similar skill, as the first player will win with correct play on any board size.

Misere Y

In this inversion, the player who first connects all three sides loses rather than wins. Misere Y changes the strategic logic considerably: players must extend toward two sides while deliberately avoiding the third, and the endgame becomes a tense exercise in forcing the opponent to complete their own chain.

Handicap play

A stronger player begins the game with one or more of their stones already placed on the board, chosen by the weaker player before the game starts. The number of pre-placed stones is adjusted until both players win roughly half their games in a series. This is a practical way to play enjoyable games between players of unequal experience.

Y: frequently asked questions