Symple is a thematic blend of territory and dynamic connection, rewarding a point for every stone a player has placed on the board, but subtracting an even number of points for every separate group. The game is played on an odd sized square board, whereby different sizes are possible. The diagram shows a standard base-19 board. An odd sized board and the even group penalty make that the game cannot end in a draw.
- A 'group' consists of orthogonally connected stones of one color. A single stone is a group by definition. The orthogonally adjacent vacant points of a group are called its 'liberties'. A group that has at least one liberty is called a 'live' group. A group without liberties is called 'dead' because it can no longer influence the outcome of a game.
There are two players, Black and White. Both have a sufficient number of stones in their color. The game starts on an empty board. White moves first. Moving is compulsory.
On his turn a player must either:
Top-right a similar situation, but now black may still grow the rightmost group at the cells marked with a white circle. He connects to an already grown group, but no group "as they existed at the beginning of the turn" grows more than one stone.
Note: a player is free to choose the order of growth. A group is not allowed to grow if a stone at any one of its liberties, would at the same time grow another group that did already grow in the same turn. This is a regular endgame occurence and makes the order in which to grow part of the tactical considerations.
In the center, the marked white stone connects four groups. No further stones may be added to the resulting group in this turn, and of course he now may only grow one stone at it in his next turn.
At the bottom white has grown the marked stone. Now cell marked 'X' is off limits, but the cell marked with a white circle is still optional for growth.
The game ends by one player's resignation or when the board is full.
The winner is now the player with the highest score. A player's score is counted as the number of stones he has placed on the board minus P points for every separate group, where P is an even number, agreed upon beforehand.
Note: This parameter is central to the theme. The applet allows P to be set at 4, 6 ... 12, because these would seem to give the most interesting play. The nature of the game's strategy changes with the choice of the parameter.
The dilemma is, to a substantial degree, how long to create new groups and when to start growing them. More groups are needed to be able to grow faster in the subsequent turns, but the more groups there are, the more tempting it becomes to be the first to grow, because of the initiative the combination of several growing moves allows.
Within the main dilemma, the move order balancing rule creates its own dilemma. Both players are faced with the choice of trading the move order advantage against the growth of a limited number of groups by the opponent, as is pointed out in About Symple. Symple is a drawless, finite perfect information game for which an opening advantage for either player cannot be argued successfully.
Barring black's prerogative, the provisional concensus for starting to grow is upward from the square root of half the number of cells of the board. Base-19 that's around move thirteen or fourteen, although tactical developments may induce earlier growth.
The opening stones should be placed so as to be able to secure as much territory for potential growth as possible. Having the edge of the board in the back is a good means for that, so 'go-like' play along the edges seems natural. Keeping groups disconnected is also crucial in this stage, to ensure prolongued growth potential.
Towards in the endgame, when growth potential has severely diminished, opportunities may arise to get points by cutting the opponent's groups or connecting one's own.
Invasions: It may be favorable to start a new group within the 'opponent's territory', if it can grow enough to outgrow it's negative starting value. That of course depends on the value of P: the higher it is set, the more stones are needed to create a group that contributes positively to the score, and the more difficult invasions will become. It may be very unfavorable to be forced to start a new group because the growing options have run out. This is an important factor deep in the endgame, if and when a player runs out of live groups.
Symple's character is that of a pure strategical game, where small tactical advantages must accumulate on a sound positional strategy. In balanced games however, and those are the only ones to get there in the first place, the endgame offers tactical issues regarding the connection of groups or the forced creation of new ones, that will sharply increase the tension and drama.
The applet continually displays the score as well as its composition.