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-left black has grown one group (the marked stone). Now he may not grow the other group at the cell marked 'X', because the first group would have two new stones adjacent to it.
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 only the two newly grown stones touch, so the move is legal.
Note: a player is free to choose the order of growth. A group is not allowed to grow if the placement of a stone would at the same time grow another group that did already grow in the same turn. The choice it presents is a regular endgame dilemma 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 initial dilemma is to a substantial degree how long to place single stones and when to start growing them. More groups are needed to be able to grow faster in the subsequent turns, but the more singles there are, the more tempting it becomes to be the first to grow. The combining of growing moves gives an initiative, and taking it becomes increasingly tempting.
Within the main dilemma, the move order balancing rule creates its own dilemma. Both players are faced with the choice of trading the turn 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. Not many such games exist.
Barring the settling of the turn order advantage, the provisional concensus for starting to grow on a base-19 board is around move 12, although it may depend on the height of the group penalty. Tactical developments may also 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 is only favorable to start a new group within the 'opponent's territory', if it can outgrow it's own negative starting value and the inherent forfeit of a growing turn. 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 one's growing options have run out. Towards the endgame these options increasingly diminish.
Symple's character is that of a pure strategical game, where small positional advantages and clever tactics should serve a sound strategy. In balanced games, and those are the only ones to be considered in this context, 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.