Noughts and Crosses
The first of the centre's board games: noughts and crosses three ways - the classic 3 by 3, Ultimate with its nine boards in one, and five in a row on a 15 by 15 board - with a friend, or the computer in the other seat.
Three games
- Noughts and crosses: three of your marks in a row - across, down or corner to corner - on a 3 by 3 board. Played well by both, it is always a draw: a game to learn, and for children.
- Ultimate: nine small boards make one big one. The square you play in sends your opponent to the board in the same place, lit for them; win a small board with three in a row, and three boards in a row to win. Real strategy, in a few minutes.
- Five in a row - gomoku - on a 15 by 15 board: five or more of your marks in a row wins, and an open four cannot be stopped.
At the table
- Two at a table, a person or the computer in each seat; or play alone against the computer whenever you like.
- Whoever sets a table up chooses its game, how well the computer plays - gently, steadily or its best - and whether hints are given.
- X moves first, and the first move goes to each player in turn, game by game; the table keeps the tally. Either player may resign.
- Leader boards ranking a room's players by their points a game, a win a point and a draw half; and each game for visitors to try.
How our computer players think
Nothing is hidden in these games, so the computer sees exactly what you do - and each game asks for a different way of thinking.
- Noughts and crosses: it searches every game to its end. At its best it never loses; steadily, it now and then plays a move at random; gently, it takes a win when it sees one and blocks you only half the time.
- Ultimate: too many games to search to the end, so it plays them out at random from each move - up to 20,000 times at its best - growing a tree of the moves that do best, and plays the one tried most: Monte Carlo tree search.
- Five in a row: it weighs every square near the marks by the rows of five it would be part of, its own and yours it would stop. At its best it first takes five, stops yours, makes four two ways, or stops you doing so.
- Ask for a hint and it lights the move it would make, and says why.
The other games
Back to the centre; how to find your way around, and what it costs (nothing): frequently asked questions.