Alignment games
This game was invented by 日出 (Richu) from Guangzhou, China. The Romanized version of the title is Xingqi (pronounced "Shingchee"). Shape Chess caught my attention right away, for two reasons.
Foremost, I was struck by its goal: when charting win conditions of abstract games, I didn’t encounter this one. It’s a pattern game in the sense that making specific shapes is necessary to win. Classically, this means explicitly specified patterns, always understood up to translation, reflection, rotation. Oldest are lines of fixed length, as in Connect4, Renju, Connect6. Other games ask for squares where the size is generally not specified, as in Quartetto or Morelli. Sometimes there is a set of possible patterns: in Hexade, Sanqi or Six, the goal is to make a line, triangle or ring out of six stones on a hex board. Going beyond specified patterns, Manalath is partially about forming a hex pentomino—here the winning pattern is specified by size (there are 22 hex pentominoes). Deviating from all that, Shape Chess defines the patterns by a geometric property: mirror symmetry.
The other striking feature of this game is its origin: it is the product of a gaming community I never heard of before. By chance, Kerry established contact with a group of Chinese players and designers of abstract games, and Shape Chess is one of their fruits. I am imagining that one can see the unique style of that group reflected in the rules.
The rules
2. the player scores n − 5 points for a shape of n ≥ 6 stones,
3. the player takes another turn.
For me, the symmetric shapes and the push action took getting used to, so here are diagrams explaining the rules. The diagram below deals with shapes. Note that two of the white positions have a rotational symmetry but do not count as symmetric shapes according to the rules. The three black shapes are all symmetric, each consists of six stones and would score one point:
Foremost, I was struck by its goal: when charting win conditions of abstract games, I didn’t encounter this one. It’s a pattern game in the sense that making specific shapes is necessary to win. Classically, this means explicitly specified patterns, always understood up to translation, reflection, rotation. Oldest are lines of fixed length, as in Connect4, Renju, Connect6. Other games ask for squares where the size is generally not specified, as in Quartetto or Morelli. Sometimes there is a set of possible patterns: in Hexade, Sanqi or Six, the goal is to make a line, triangle or ring out of six stones on a hex board. Going beyond specified patterns, Manalath is partially about forming a hex pentomino—here the winning pattern is specified by size (there are 22 hex pentominoes). Deviating from all that, Shape Chess defines the patterns by a geometric property: mirror symmetry.
The other striking feature of this game is its origin: it is the product of a gaming community I never heard of before. By chance, Kerry established contact with a group of Chinese players and designers of abstract games, and Shape Chess is one of their fruits. I am imagining that one can see the unique style of that group reflected in the rules.
The rules
- Any square board of size 12×12 or larger, for example, a Weiqi ( Go) board of size 13×13 or 19×19, or a 15×15 Renju board.
- A shape is a stone together with all same-coloured stones that can be reached by orthogonal or diagonal steps. A shape is symmetric if it is preserved by reflection along a line.
- Black begins. A turn is either a Drop, a Jump or a Push:
— Drop an own-stone on an empty point.
— Jump an own-stone from its current point to an empty point, anywhere on the board.
— Push an opposing stone to an adjacent empty point and place an own-stone at the origin. - If after a player’s turn there are symmetric shapes of ≥ 6 stones of the player’s colour, then
2. the player scores n − 5 points for a shape of n ≥ 6 stones,
3. the player takes another turn.
- The first player to reach four points wins.
For me, the symmetric shapes and the push action took getting used to, so here are diagrams explaining the rules. The diagram below deals with shapes. Note that two of the white positions have a rotational symmetry but do not count as symmetric shapes according to the rules. The three black shapes are all symmetric, each consists of six stones and would score one point:
The next diagrams explain the three types of action in Shape Chess. Each of these is relevant. The most common action is the push, followed by the drop—these add a stone which is what you generally want. The jump, on the other hand, allows splitting a larger shape into smaller ones. Used less often, it can be crucial in making, or threatening, symmetric shapes.
There is a certain symmetry to the action types if you want to see it: an own-stone can interact with an empty spot (drop), with an opposing stone (pushing it aside) or with another own-stone (making it jump in a leap of faith).
There is a certain symmetry to the action types if you want to see it: an own-stone can interact with an empty spot (drop), with an opposing stone (pushing it aside) or with another own-stone (making it jump in a leap of faith).
The last batch of rules diagrams shows how to score:
History
The first version of Shape Chess is from 2010. The goal of the game—to score symmetric shapes—was kept throughout its evolution, as was the name. Incidentally, "chess" is used in the Chinese language environment for any game requiring a board. What did change was the movement protocol, attempting to fit it best to the win condition. Previous versions had various kinds of toggle capture, like Reversi. The rules given here are from 2022 and have no such toggling. Instead there are now three types of actions, of which the push interacts with opposing stones. In this form, the game is conveniently playable with standard equipment, and I like it a lot for that. Keeping track of points is also easy: when removing the stones from a symmetric pattern, discard five stones into the bowl and put the remaining ones aside; these form your score.
Basic scoring strategy
While the goal is to accumulate points, each scoring action comes with a drawback: the loss of stones, making it easier for the opponent to build symmetric shapes and harder for oneself to rake more points. This is why it is usually better to aim for one’s first symmetric shape to contain at least seven stones. On the other hand, after having two points, it can be worthwhile to score a 6-shape. With a score of three, every future threat towards any symmetric shape is absolutely forcing.
Spotting symmetric shapes
Players have to anticipate mirror-symmetric patterns. This is an unusual task, made even harder as the position is ever-changing from all the pushes and jumps. Nonetheless, you can get a feeling for shape. In the first problem below, you are asked to create the largest possible symmetric shape with just one move. In the second problem, find a move winning immediately (this works for either side) — remember the bonus action after making a symmetric shape!
The first version of Shape Chess is from 2010. The goal of the game—to score symmetric shapes—was kept throughout its evolution, as was the name. Incidentally, "chess" is used in the Chinese language environment for any game requiring a board. What did change was the movement protocol, attempting to fit it best to the win condition. Previous versions had various kinds of toggle capture, like Reversi. The rules given here are from 2022 and have no such toggling. Instead there are now three types of actions, of which the push interacts with opposing stones. In this form, the game is conveniently playable with standard equipment, and I like it a lot for that. Keeping track of points is also easy: when removing the stones from a symmetric pattern, discard five stones into the bowl and put the remaining ones aside; these form your score.
Basic scoring strategy
While the goal is to accumulate points, each scoring action comes with a drawback: the loss of stones, making it easier for the opponent to build symmetric shapes and harder for oneself to rake more points. This is why it is usually better to aim for one’s first symmetric shape to contain at least seven stones. On the other hand, after having two points, it can be worthwhile to score a 6-shape. With a score of three, every future threat towards any symmetric shape is absolutely forcing.
Spotting symmetric shapes
Players have to anticipate mirror-symmetric patterns. This is an unusual task, made even harder as the position is ever-changing from all the pushes and jumps. Nonetheless, you can get a feeling for shape. In the first problem below, you are asked to create the largest possible symmetric shape with just one move. In the second problem, find a move winning immediately (this works for either side) — remember the bonus action after making a symmetric shape!
Secure shapes
During play, sprawling clusters often form. As the number of stones on the board grows, so do the opportunities to make a symmetric shape. Of particular value are patterns that can be made symmetrical in many ways. For example, symmetry along grid lines and diagonals is easier to make and to extend than symmetry along half-grid lines.
An asymmetric shape of size six or larger is called secure if the opponent cannot prevent it from becoming symmetric in a single turn. Here are some secure shapes. If White is going to do something about it (not always necessary because Shape Chess is a game won on a score, not on a particular board position) then the best bet is to push a black stone away, making the shape smaller:
During play, sprawling clusters often form. As the number of stones on the board grows, so do the opportunities to make a symmetric shape. Of particular value are patterns that can be made symmetrical in many ways. For example, symmetry along grid lines and diagonals is easier to make and to extend than symmetry along half-grid lines.
An asymmetric shape of size six or larger is called secure if the opponent cannot prevent it from becoming symmetric in a single turn. Here are some secure shapes. If White is going to do something about it (not always necessary because Shape Chess is a game won on a score, not on a particular board position) then the best bet is to push a black stone away, making the shape smaller:
Note that these secure shapes aren’t equally valuable to Black either: two of them can be made symmetric only by a jump (which ones?), the others by a drop. The latter is more attractive for its additional point.
The three actions: drop, jump, push
On each turn, a player has to choose the type of move. Drops and pushes add an own-stone to the board which is generally desirable. Jumps allow one to split shapes. Often, drops and jumps have no strong impact on the opponent’s position because the other player can push the stone away — unless that stone has no liberties. Therefore the main interaction, including defence, is pushing and that’s why it is the most common move in Shape Chess.
A pushing battle. Here is a sequence of pushing moves coming from a real game
The three actions: drop, jump, push
On each turn, a player has to choose the type of move. Drops and pushes add an own-stone to the board which is generally desirable. Jumps allow one to split shapes. Often, drops and jumps have no strong impact on the opponent’s position because the other player can push the stone away — unless that stone has no liberties. Therefore the main interaction, including defence, is pushing and that’s why it is the most common move in Shape Chess.
A pushing battle. Here is a sequence of pushing moves coming from a real game
This kind of sprawling growth is typical for the opening. Each move 1, 2, 3 is a1-point threat and 4 is a 2-point threat. Afterwards, the shapes are too large and twisted for immediate threats. Again, this is common and once this stage is reached, jumps become attractive.
When White places 3, that stone has no liberties left, i.e. empty adjacent points where diagonally adjacent points are included. Thus this white stone is fixed for the time being, and exactly the same holds for 4. Pushes have one limitation in being short-ranged but they are also sensitive to the position of opposing stones. This means that when there is no need to react to a threat one is often better off with a drop or jump.
Jump. These provide flexibility as they can connect or dissect shapes. The double threats so typical in pattern games often arise in Shape Chess from jumps. Sometimes, they can perform defensive duties too.
In the following position, White uses a jump to split a large shape into two, setting up a double threat: jumping either A to a or B to b scores three points. White is active and on the attack.
When White places 3, that stone has no liberties left, i.e. empty adjacent points where diagonally adjacent points are included. Thus this white stone is fixed for the time being, and exactly the same holds for 4. Pushes have one limitation in being short-ranged but they are also sensitive to the position of opposing stones. This means that when there is no need to react to a threat one is often better off with a drop or jump.
Jump. These provide flexibility as they can connect or dissect shapes. The double threats so typical in pattern games often arise in Shape Chess from jumps. Sometimes, they can perform defensive duties too.
In the following position, White uses a jump to split a large shape into two, setting up a double threat: jumping either A to a or B to b scores three points. White is active and on the attack.
Final problem
Solutions to the three puzzles are here.
Concluding remarks
Hopefully I could convince you that Shape Chess brings something new to the abstract board game table. Another scoring game whose points come from patterns, and perhaps closest in spirit, is Yinsh (Kris Burm, 2010), where lines-of-five are scored. In both games, scoring shapes are removed by self-capture—a natural mechanism creating tension between scoring and a weakened board position. Moreover, either game is over if a certain score threshold is reached (four in Shape Chess, three in Yinsh).
By the way, Shape Chess has an unusually high branching rate. This comes from its three actions, and there are already very many pushing moves in any midgame position. Moreover, unlike sudden-death pattern games, such as Renju, playing for a score threshold allows for tactical tenuki (i.e., not answering a scoring threat).
As with most point-scoring games, players of different skill can introduce a handicap by letting the weaker player start with one or two points. Because Shape Chess games end on reaching a point threshold, players can also agree to use a limit other than four for a longer or shorter match.
The game is actively played in the mainland Chinese online network QQ Channel. There, ten players had a tournament running from July 15 to August 14 2022. Some beautiful winning patterns from this tournament are shown below. It’s hard to take part in QQ from elsewhere, especially if unable to write Chinese. However, there are attempts to reach out: the game has a BoardGameGeek entry and is playable in Ai Ai. Hopefully, online playing for English speakers will come too. ◾️
Concluding remarks
Hopefully I could convince you that Shape Chess brings something new to the abstract board game table. Another scoring game whose points come from patterns, and perhaps closest in spirit, is Yinsh (Kris Burm, 2010), where lines-of-five are scored. In both games, scoring shapes are removed by self-capture—a natural mechanism creating tension between scoring and a weakened board position. Moreover, either game is over if a certain score threshold is reached (four in Shape Chess, three in Yinsh).
By the way, Shape Chess has an unusually high branching rate. This comes from its three actions, and there are already very many pushing moves in any midgame position. Moreover, unlike sudden-death pattern games, such as Renju, playing for a score threshold allows for tactical tenuki (i.e., not answering a scoring threat).
As with most point-scoring games, players of different skill can introduce a handicap by letting the weaker player start with one or two points. Because Shape Chess games end on reaching a point threshold, players can also agree to use a limit other than four for a longer or shorter match.
The game is actively played in the mainland Chinese online network QQ Channel. There, ten players had a tournament running from July 15 to August 14 2022. Some beautiful winning patterns from this tournament are shown below. It’s hard to take part in QQ from elsewhere, especially if unable to write Chinese. However, there are attempts to reach out: the game has a BoardGameGeek entry and is playable in Ai Ai. Hopefully, online playing for English speakers will come too. ◾️
🔴⚫️🔴⚫️🔴⚫️🔴
Lastly, here are two pictures of children playing Shape Chess in a tournament in China. For how many other recent abstract games would we be able to find similar images? ~ Editor
Games mentioned
- Connect4: Ned Strongin, Howard Wexler, 1974.
- Renju
- Connect6: I-Chen Wu, 2003.
- Quartetto: Artyom Tchebotaryov, 2008.
- Morelli: Richard Moxham, 2011.
- Hexade: Christian Freeling, 1992.
- SanQi: L. Lynn Smith, 2003.
- Six: Steffen Mühlhäuser, 2003.
- Manalath: Dieter Stein, 2012.
- Reversi: John W. Mollett, Lewis Waterman, 1883.
- Yinsh: Kris Burm, 2010.