Bridge-It

Rules — Bridge-It

• There are two grids of dots, one slotted inside the other: blue dots and maroon dots.
• On your turn you build one bridge between two neighbouring dots of your own colour, across or down.
• Bridges may not cross. Each bridge you build blocks exactly one of your opponent's — the one that would have crossed it.
• Blue wins by joining the top edge to the bottom edge. Maroon wins by joining the left edge to the right edge.
• There are no draws: when the board fills up, exactly one of the two has connected. Always.

Levels:

• Level 1 — small board (4).
• Level 2 — medium board (6).
• Level 3 — big board (7).

Against the computer you choose your colour, and that decides who moves first: blue always opens. It matters more than you would think.

Blue builds one bridge downwards. Look at what it costs maroon: the maroon bridge marked ✕ can never be built now, because it would have to cross the blue one. Every bridge does this — it takes exactly one bridge away from the other player, no more and no less.

That is the whole mechanism, and it is also why there are no draws. When no bridge can be added anywhere, blue's bridges either reach from top to bottom, or they don't — and if they don't, what stopped them is a solid maroon wall from left to right. One of the two, never both, never neither.

So each move does two jobs at once: it advances your own road and it cuts one of theirs. When you are choosing, ask which of the two matters more right now.