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Reversi: how to play

Reversi is one of the games in Classic Nook, a cosy shelf of classic games. Play Classic Nook or see all the Classic Nook games.

The idea

Reversi is played on an 8 by 8 board with Ruby and Sapphire gems. You place a gem so that it traps a line of your opponent's gems against one of your own, and the trapped gems flip to your colour. When the board is done, whoever has more gems wins.

Opening it

In the Classic Nook hub, tap Reversi on the shelves. Pick a mode on the menu to start. The house button at the top left always takes you back to the shelves. In a round, the back arrow next to it returns to the game's menu, and the ? button shows a short reminder of the rules.

Controls

Tap a square on a phone or tablet, or click it with the mouse on a computer, to place a gem. Soft dots on the board show the squares where you can play. Under the board are Undo, Hint and Restart.

The rules

1. The board starts with four gems in the middle, two of each colour. Ruby goes first. Against the computer, who goes first alternates from round to round.
2. On your turn, place a gem on an empty square so that, in at least one direction (across, down or diagonally), a line of your opponent's gems sits between your new gem and another gem of yours.
3. All the gems trapped that way flip to your colour. One move can flip lines in several directions at once.
4. If you have no legal move, your turn is skipped, and the game tells you. The same goes for your opponent.
5. When neither side can move, the round ends. The side with more gems wins, and equal counts are a draw. The end card shows the final count.

Difficulty levels and two players

Choose Play the computer and then a level, or choose Two players.

• Easy: the computer plays mostly at random, but takes a corner half the time.
• Medium: it looks three moves ahead.
• Hard: it looks six moves ahead and plays out the last eight moves exactly. About one move in ten it slips to a random move that does not give away a corner, so it is strong but beatable.
• Two players: two people share one device and take turns, Ruby first. There are no coins to win, and Undo, Hint and Restart are free.

Coins, Hint and Undo

The whole Classic Nook collection shares one coin count, shown at the top. You start with 30 coins, and you get a gift of 30 coins the first time you come back on a new day.

• Hint costs 15 coins and marks the best square for you, using the same six-move search as the Hard computer, without its slips. It only works on your turn.
• Undo costs 10 coins and takes back your last move and the computer's reply, flips included, so it is your turn again. After a loss, the end card also offers Undo for 10 coins, and the loss is taken out of your record.
• Restart is free if the round is over or you have made at most one move. After that it costs 5 coins. A restart in the middle of a round is not a result, and the same side starts again.
• Against the computer only. In two-player rounds all of these are free.

What is saved

Your coins, your record for each mode (won, drawn, lost; in two-player mode, Ruby won, drawn, Sapphire won), who goes first next, and the sound setting. The record is on the menu, and it is all kept between visits.

Tips

• Corners are gold: a gem in a corner can never be flipped. Grab them when you can.
• Be careful with the squares right next to an empty corner, because they can hand that corner to your opponent.
• Having fewer gems in the middle of the game is not a problem. What matters is having more choices than your opponent.
• Do not flip too many gems too early. Every gem you own gives your opponent a line to trap.
• Use the dots to compare your options before you tap, and pick the one that gives your opponent the fewest.
• Try a Hint on a position you cannot read. It is a good way to learn what strong moves look like.

Questions or problems? Contact us.