Basic Rules

SUMMARY: Gyre is a board game where players alternate turns to try to control as much area of the board as possible using a point system (see Scoring, below).

The board is arranged as a grid of tiles. Tiles are initially unoccupied.

Figure 1

Each player completes his turn by claiming an available tile. Available tiles are tiles not already occupied. In addition to tiles, there are gyres. Gyres are located at the intersections of the tiles.

Figure 2

At the start of the game all gyres are unowned so are not displayed. During play, a player may acquire gyres. Gyres that are owned are displayed in the color of the player who owns the gyre.

A player's turn consists of two things:

• Operating a gyre - a gyre is used by drawing an arc around it. This gesture tells the gyre to move the tiles bordering the gyre around it in the direction indicated. This is called gyrating the tiles.
• Claiming a tile - a tile is claimed by tapping it. If the tile just claimed is next to an opponent tile, any unclaimed gyres at the intersection are also claimed. Claiming a tile next to one's own tile does not result in a gyre being claimed. Claiming a tile completes a players turn.

The turn ends when a tile is claimed. If claiming a tile results in also claiming a gyre, the gyre will be added to the board when the tile is claimed. Once a gyre is claimed by a player, that player owns that gyre for the remainder of the game. Controlling gyres thus becomes an important strategy.

Figure 3 Here red plays first. Blue claims a tile next to red's tile. That gyre is not yet claimed, so claiming this tile for blue also claims the gyre shared by the opponent tiles. This will remain a blue gyre for the remainder of the game even if those stones are moved away from the gyre.

Figure 4 In this illustration, play continues where the previous illustration left off, with red playing below the tile claimed by blue. Red thus claims two gyres, the unclaimed at the intersection of the tile just played and the opponent tile. Blue then claimed the top tile next to the red one, claiming another gyre. Finally, red plays, first by gyrating four tiles using the gesture indicated in yellow. The center of that gesture is indicated by the white square. The gyre touched by that white square is owned by red, so the tiles around it are gyrated around the gyre. Red completes the turn by claiming another tile. All gyres touching the tiles being gyrated are deactivated until the end of the turn. The player may continue with other gyrations using active gyres, if available.

SCORING: The total score for a player is the some of the sores for all the tiles occupied by that player. The score for a tile is calculated as follows: Start with 1 if the tile is occupied. Then multiply by 2 for each neighbor occupied by the same color. Finally, subtract 1 for each tile occupied by an opponent.

Scoring examples:

Figure 5 Score is 1.

Figure 6 Score is 2 for each tile.

Figure 7 Score for center tile is 64.

Figure 8 Score for center tile is 62. Score for top, right blue tile is 1-3 = -2. Score for bottom, left blue tile is 1-5 = -4.

Figure 9 Tap an occupied tile to see a popup showing an explanation for the score for that tile. Shown is the popup for the center red tile in Figure 8.

Instead of displaying the scores of the tiles, the tiles are shaded according to the score. The higher the score, the closer the tile color is to the stone's color. Negative scores are colored faint yellow. The highest possible score for a tile is 256 for a tile completely surrounded by other tiles occupied by the same player. The lowest possible score is -8 for a tile completely surrounded by enemy tiles. However, the lowest possible score for two players is -7, because -8 results in a capture. The score is displayed at the top of the screen using a score bar. The score bar contains text for the score as well as color to graphically indicate the score. The relative amounts of color on this bar correspond to the scores of the players with those colors.

Figure 10 Red player has a score of 108. Blue has a score of 190. Additionally, red controls 10 gyres, and blue controls 9 gyres.

CAPTURING TILES: Once a tile is claimed by a player it remains occupied by that player unless it is captured by an opponent. An opponent can capture a tile by completely surrounding it (all 8 surrounding tiles must be occupied by the capturing player). This can be accomplished by gyrating tiles or by claiming a tile. Tiles thus surrounded are captured and become the property of the player who surrounded the tile.

GESTURES: The following gestures are used to play the iOS version of the game.

• TAP - a tile is tapped to claim it. Tapping a previously unclaimed tile results in the tile being claimed. The player claiming the tile then occupies it until the end of the game or until it is captured. This action finishes the player's turn, and play continues with the next player. Tap an occupied tile to see a popup of how the score for that tile is calculated.
• TAP (on score bar) - resets the game starting a new one.
• ARC - a gyre is operated by using the ARC gesture (illustrated in Figure 4). An ARC gesture is performed by drawing an arc shape around a gyre. The app calculates the center of the arc and finds the closest gyre to that center. If that gyre is controlled by the player who drew the arc, the tiles around the gyre will be gyrated in the direction the arc was drawn. When tiles are gyrated, all gyres located at the corners of those tiles are deactivated until the turn ends by claiming a tile. 
• PAN - using two or more fingers, a user may recenter tiles on the board. Topologically, the board is arranged as a torus, so it can be panned in any direction. Tiles that move off an edge by panning, reappear on the opposite edge.
• SWIPE - Swiping horizontally to the right undoes the last action. Swiping horizontally to the left redoes an action just undone.

Be careful when using the ARC gesture. You must draw the arc so that its size is less than the width and height of two tiles. Just keep the arc within the square bounding four tiles. If the gesture exceeds 2 tiles in height or width, it will be interpreted as a swipe instead. However, a swipe will not be performed unless it is horizontal. Any other gesture is ignored.

SETTINGS: Various options can be set using the iPhone Settings app.

Figure 11 Open the device Settings app to view or change application settings (see figure 12).

Figure 12 Game settings

Version - the version of the app.
Build - the build of the app (there can be multiple builds for a version).
Players - select from 2 to 4 players.
Tiles Across - select how many tiles across to use when laying out the board.
Enable 2-finger Rotation - by default, rotation is performed using the ARC gesture. However, it can be switched to use the standard 2-finger rotation gesture instead. Use caution when changing to this gesture, however, since it is not as useful near the edge of the screen.
Enable Arc Rotation - If 2-finger rotation is enabled, arc rotation may be disabled here. If both are disabled, the app will reenable the arc gesture.
Show Gestures - if enabled, graphical depictions of the gestures, as in Figure 4 will be shown. This can be useful if gestures are not being recognized as expected.
Show Gyre Count - (see Figure 10) if enabled, the number of gyres owned by each player is shown in parentheses () following the score - if disabled, gyre count is omitted.
High Score - Upon completion of a game, the high score is saved here. The high score is the difference between the winner's score and the next highest score.