Pentobi's main window shows the board on the left side. The played pieces on the board can have numbers on them that indicate the move number in which the piece was played. An letter after the move number indicates that there exists a variation to this move (see below).
Pieces can be played by moving them to a place that corresponds to a legal move with the mouse or arrow keys and pressing the left mouse button or the Enter key.
On the right side, the remaining pieces are shown. Above the remaining pieces is an orientation selector that shows the currently selected piece and allows the player to change its orientation. If no piece is selected and the game has not yet ended, a colored dot in the orientation selector shows the color to play.
Pieces can be selected by clicking on one of the remaining pieces shown, by using the left/right arrow buttons in the orientation selector or by using shortcut keys.
Below the orientation selector is a score display, which displays the current points for each color or player. The points are the sum of on-board points and bonus points. Points are underlined if they are final because the color cannot play more pieces. A small star indicates that the points include a bonus.
The board can be used for creating game records of games played by humans or for playing games against the computer. In games against the computer, the computer can play any (or several) of the colors.
When you start a new game, the human will play the color(s) of the first player by default and the computer all other colors. To change this, use Computer Colors from the Computer menu or toolbar and select the colors the computer should play.
The exception is that the computer will play no color by default if it played no color in the previous game. This prevents the computer from automatically starting to play if the user mainly wants to use the board for entering move sequences or similar editing tasks. So if you want to use the board without playing against the computer, you need to disable the computer colors in the Computer Colors dialog only once and it will stay that way. After loading a saved game, the computer also plays no color by default.
Selecting Play from the Computer menu or the toolbar always makes the computer play a move for the current color. If the computer did not already play this color before, it will also make the computer play this color (and only this color) from now on.
When you play a game, Pentobi will store the sequence of moves and it is always possible to go back to a previous position and play differently. If you do this, the new sequence is stored as an alternative sequence (called variation). Variations can also be used by annotators for commenting on existing games. Variations can exist at any board position and can have subvariations themselves. The game can therefore become a game tree, in which each node represents a board position. You can navigate in the game tree with the items in the Go menu or in the toolbar.
The main variation is the sequence of moves that starts at the start position and always selects the first child node in each position (e.g. by selecting Forward in the Go menu or toolbar). The main variation is supposed to represent the real game played. If you want a side variation to become the main variation, select Make Main Variation from the Edit menu.