Go == The Equipment ------------- Acornsoft Go is played on a board ruled with 13 horizontal lines and 13 vertical lines. Play takes place on the points of intersection of the lines rather than the squares. The board is initially empty. The game is for two players who play alternately by occupying a vacant intersection with a piece (called 'stone') of their colour (Black or White with Black starting). The Object Of The Game ---------------------- The main object of the game is to occupy territory; a second object is to capture enemy stones. A single stone is captured when it is directly surrounded along the lines by opposing stones. Two or more stones of the same colour which are joined together along the lines stand or fall together; the whole group is captured if it is directly surrounded along the lines. A player may pass at any time. The only restrictions are the special ko'rule which prevents repetition of a position and the 'suicide rule. The program enforces these rules and, during a 'ko', the word 'ko' is displayed above the board. Detailed explanations of these rules are given later in this booklet. The End Of The Game ------------------- The game ends when three successive passes have occurred. The program then calculates and displays the score. This program employs the Chinese scoring rules in which no points are scored for captured enemy stones (unlike the Japanese rules) but you score one point for each intersection surrounded and one point for each of your stones left on the board at the end. Make sure that you complete the capture of all trapped stones (dead groups) before finally passing; if dead groups remain the score will be inaccurate, but you can still play on. If the total of the two final scores is greater than 169, the game isn't finished because there is some territory that the program thinks is occupied by both sides. Since Acornsoft Go will only allow you to make legal moves, there is nothing to stop you from letting the program teach you how to play. A Beginner's Guide To Go ------------------------ Background To Go ---------------- Go is the Japanese name for an ancient board game with a tradition in the Far East going back thousands of years. Generations of professional players have made studies in Go comparable in depth to those by the chess grandmasters. The game requires strategic insight, intuition as well as a strong calculating mind. Recently Go has been gaining in popularity in the Western World. Definitions ----------- Connections: Two stones of the same colour are directly connected if they are joined along a line. A collection of stones of the same colour linked by direct connection is called a group Liberties: The liberties of a group are those intersections adjacent to it along the lines of the ruled grid. For example, a single stone in the centre of the board may have four liberties; stones on the edge of the board have, at most, three liberties and in the corner they have only two. Capture: A group is captured when an enemy stone is played to fill its last liberty. In the Acornsoft program the word 'atari' is displayed at the top of the screen when a group is in imminent danger of being captured. Groups must be captured en masse; individual stones cannot be picked off one by one. In figure 1 there are two groups. It is important to note that connections across the diagonal do not count and therefore the two groups are not connected in any way. [] In figure 2, the two groups in figure 1, have had their liberties, bar one, occupied by enemy stones, ie subject to capture on the next move. [] In figure 3, the last liberties have been occupied and the groups captured and removed from the board. [] The 'Suicide' Rule ------------------ Playing your own army into a situation without liberties is illegal. However, it is permitted to play into such a position if the stone played completes a capture. For example, in figure 4, the Black group can be captured if White plays at E3. [] The 'Ko' Rule ------------- Some common situations in Go could lead to a repetition of position and so require a special rule. Figure 5 shows three simple positions in which a single stone may be captured, only to be subject to immediate recapture (see figure 6). The rule of 'ko' (a Japanese term) applies to any situation of this kind, where a single stone is captured and a single recapture would restore the initial position. The rule states that after the first capture in such a position, the second player must not recapture immediately. After the second player's turn, this restriction lapses. [] In practice, if the recapture is important, the player makes a play in some other part of the board requiring an instant reply ("ko threat') and then recaptures - the boot is then on the other foot. Long sequences of 'ko threats' are a common and exciting part of the game, involving delicate calculations of profit and loss. Safe Groups ----------- As the game proceeds, the board gradually fills up. The stones sort themselves into collections of armies which are potentially, if not directly, connected - these are called 'groups'. A basic Go skill is to make groups immune from capture by ensuring they enclose enough empty territory. The principle behind every safe group is the same, and is known as 'two eyes' (an 'eye' being a vacant intersection within a group). In figure 7, for example, the Black group is safe (barring Black blunders), because White needs to play at Al and C1 simultaneously (which is impossible). [] The Handicap System ------------------- The player with the black stones always has a slight advantage since Black always starts. A larger advantage is given by allowing Black to play up to nine stones before White plays. To discover your handicap against the computer or a human opponent, adjust the number of handicap stones after each game. Hints ----- 1. Armies with one liberty may be captured; armies with two liberties are very vulnerable and may be subject, by a forcing sequence, to capture. 2. Saving threatened armies may lead to greater losses-small armies are often sacrificed. 3. The connection of armies to form a larger army with more liberties avoids losing stones piecemeal. 4. It is normally good practice to prevent the opponent's armies connecting, especially if one army is short of liberties. 5. Don't neglect territory formation - you cannot expect to win every game by capturing massive groups of stones. Game Controls ------------- Arrow Keys - Up/Down/Left/Right, RETURN - Places the stone on the board The game normally starts with the player playing black (first move) and then the computer plays white. ESCAPE - Restarts game: this must be verified by pressing either Y (yes) or N (no). K - Keyboard on/off (usually on); the letter K is displayed above the board. J - Joysticks on/off (usually off); when on, the letter J replaces K above the board. T - Thinking on/off (usually off); when on, the letter Tis displayed above the board. This function enables you to watch the computer thinking. 1/2 - Level 1 or 2 (usually 1); the number chosen is then displayed next to the letters Lv above the board. M - puts the program into manual mode so that two players may play Go on the graphically displayed board. In manual mode the letter M is displayed above the board. Press C to go back to playing the computer. C - Makes the computer play the current move, and then carry on playing that colour. Thus to play white against the computer press C after starting the game. A - Puts program into auto-mode (the letter A is displayed above the board) so that the computer will play against itself. Press M to switch back to manual mode. B - Takes you back one move if you are in manual mode or back to your previous move if you are playing the computer. ? - Hint option; the computer plays your next move and then continues the game. If you don't like the 'hint' press B (see above). P - Pass your move and let your opponent play again. After three successive passes the program will display the score; to continue playing press the Space Bar. H - Handicap play; to play a handicap game press H followed by the size of the handicap (1-9). You may now place that many black stones on the board (and White will pass). Alternatively, you can then press C to give the computer the handicap with you playing white. Joystick Controls ----------------- Use the joystick to move the cursor around the board. Press the fire button to place a stone on the board. Loading ------- Tape: CHAIN"" (RETURN) Disc: SHIFT-BREAK