Other Pieces

return to Variations on Go

Having collected an army and concentrated his forces,
he must blend and harmonize the different elements thereof
before pitching his camp.
[Sun Tzu, The Art of War - VII.2]

In traditional GO, there is just one piece. Let's call it the soldier. 

Unlike Chess, where there are a collection of different pieces having strange and dynamic movements, Go pieces are static and their force come from subtle influence and not from a strong and direct attack. 

Since the Go board is intended to represent a battle field and the soldier is a very weak piece taken alone, there should not be great differences between the pieces (for e.g., a chess Queen would be a very unbalanced piece inside a Go army). Also, the context of Go is an ancient or - at most - a medieval one, new pieces should try to reflect these concerns.

 

• Static pieces

Here a short list of some pieces that does not move, but have different effects on the battle.

	Ambassador Any piece touching an ambassador (blue piece) cannot capture or be captured. Also, a drop near an ambassador cannot capture. In the left example, both players cannot play at [1], since that would mean a capture in the surroundings of an ambassador.
	Bomb When a player drops a bomb (red piece) he decides between two states: a) immediate explosion: the bomb once it is dropped destroys all neighbors (and itself); and b) indirect explosion: the bomb only explodes when it is captured, destroying all neighbors (and itself). The destroyed pieces do not count as prisoners in both states.
	Wall (or Pit) A wall is an uncapturable neutral piece. This means that the maximum liberty of the neighbor cells are reduced by 1. In the example, cells [1] are in Atari. The white piece cannot escape from the black siege.
	Monk Any piece dropped within a distance of two cells of a Monk (green piece), cannot be used to capture other pieces. In the left example, Black cannot drop at [1] since [1] is within the Monk's influence area. However, White can drop at [2] to capture the black soldier.
	Spy A spy (violet piece), when dropped, changes the color of the adjacent soldiers (black turns white, white turns black). After that, its own color changes to the player's color, and then all eventual captures are done. The left example shows what happens (in clockwise fashion) when a spy is played at [1] by White.
	Tao The Tao is a 5x5 zone that enhances the soldier's mind and courage. All soldiers within the Tao's influence, can move one cell. In the example, the black stone can move all directions. However, if it moves north it will exit the Tao's influence and therefore cannot move anymore (except if a new Tao is dropped nearby).

• Mobile pieces

Here a short list of some pieces that does move. All these piece have severe restrictions and should exist in short numbers, so the soldier remains the most important piece in a Go army.

	Mercenary The mercenary (brown piece) can move to an adjacent empty cell. Any player can move a mercenary (however, the Ko rule applies). In the example, if it moves south, it captures the black piece; if it moves north, it captures the white piece. A player can capture its own pieces using a mercenary. A mercenary can be captured.
	Samurai A samurai can move like the mercenary but each one belongs to a specific player. Due to the tactical experience of the samurai, he can only move to a cell with at least three freedoms (so, it cannot move to a corner). Every friendly stone adjacent to the samurai, cannot be captured. However, the samurai himself may be captured. In the example, the white samurai can move North (the white soldier gives him the required freedom) but not East.
	Cavalry The cavalry moves like the Chinese Xiang-Qi knight (i.e., does not jump) and has the samurai's freedom restriction and powers. In the example, the black cavalry cannot move north, since the black soldier blocks his way. Also, it cannot move to cell [1], because the cell only has 2 freedoms.

So, let's give to each player an enhanced army to guide them to War.

Other possible variants:

The center of Tao All Go rules apply, except: Initially, there are four Tao pieces in the center, making a 10x10 zone where soldiers can move.

Mercenary Go All Go rules apply, except: Initially, there are nine Mercenaries placed in the handicap cells.

Buying Armies All Go rules apply, except: Attribute a price for each piece. Give an initial credit for each player to build their specific armies.

• Special powers

Some go stones may be seen as holders of special powers (the next list is a reference of this site). And remember: the threat is more dangerous than the execution.

	Life A stone that is equivalent to two eyes. This comes in two flavors: (i) only give life to friendly stones, or (ii) give life to any adjacent stone (of either color).
	Stamina A stone that when dropped allows an extra move for the player. This is very powerful to eliminate living groups with single two eyes.
	Converter A piece that is able to replace an enemy stone.
	Switcher When played, it can be later used to switch position with an enemy stone.
	Inner Strength A stone that can be placed on a suicide position. Until played, living groups need 3 eyes.
	Bridge A stone that connects any friendly stones separated by one cell (even if the in-between cell is occupied by an enemy stone).
	Taboo A stone which the opponent cannot drop adjacent to it.
	King's Son (by Stephen Loftus-Mercer) Counts as -5 if it is captured but is otherwise a regular soldier on the field.

• Group pieces

I define squadrons and platoons has groups of 3 and 4 connected pieces, respectively. In the following picture, it is displayed the possible 3 squadrons (with white pieces) and 7 platoons (with black pieces).

Other larger groups can be made. There are 15 different groups of 5 pieces (the pentominoes), 31 groups of 6 pieces (the hexaminoes), and so on...

Let's define a Go variant based on this concept:

There are two known variants based on this concept: (i) Omino Go (or Tetromino Go) by R. Wayne Schmittberger, explained in his book "New Rules for Classic Games", instead of playing one stone per turn, players drop a platoon. In Black’s first-turn, he can only play two stones, and (ii) Karl Knechtel's DominGo where both players drop 2x1 pieces (a domino) instead of single stones.

More information about polyominoes can be found at The Geometry Junkyard and in Alexandre Muñiz's Pentomination. Also, check the polyiamond, sexominoes and xominoes tilings.

• One Color pieces

Go is played with two colors (black and white). However, it's possible to imagine Go games where both players only have one type of stone (let's say gray or brown). Is it possible to imagine variants based on this premise? Some proposals:

[Martin Moller Pedersen] What about Tanbo but with two players use gray. The last player to put a stone legal on the board is the winner/loser?

[Pekka Karjalainen] [...] The players alternate placing one stone on any free space on the grid. For every square completed by the player he gains one point. First to gain M points wins the game. A square is any possible configuration of four stones that are placed so that they are at the corners of a square [diagonal squares included].

I present here another variant also based on squares:

Unsquare Go Start with the Go board full of gray stones. Then, alternating moves, each player removes a stone (that stone is not captured). When a player makes a square, he captures all stones inside that square (no diagonal squares). When there are no capturable stones left on the board, wins the player with more captured stones. If the next player removes g3, he creates a square with empty cells [1] and captures 7 stones. There is a move where it can be captured all but three stones. Where is it?

• Treasure Go (by Evan Koch)

The rules of Go apply, except:

• Before the game starts place 9 treasure stones (of a 3rd color, say red) on the board as follows: the center point, the four side (not corner) handicap points, and the four 5-5 points.
  • Place up to four handicap stones on the corner star points.

• Besides the standard Go goal, a player wins immediately if he captures a "treasure" stone!
  • So, if a game ends with neither player capturing a treasure stone, then the higher regular GO score wins.
• A treasure is captured if all four of its liberties are occupied by the same player.
  • If both players share the treasure's liberties, it is not captured  and is "in dispute".
  • For purposes of capturing, any white or black stone(s) placed against a treasure lose one liberty. In life and death battles,  a treasure has the same effect on a stone as an enemy stone would have.

Some extra notes from the author:

• A 13x13 BOARD has just four treasures placed on the following points:D7,G4,G10, and K7. They are all on the fourth line out forming a "square" around the middle.
• A 9x9 BOARD has just 2 treasures placed on C5 and G5.
• Treasures can have an interesting effect on ladders. Two stones along with the treasure can form a "tiger's mouth" for example.
• Treasure go is a big fighting game. If a player fails to make life with stones that are connected to a treasure  he/she is in serious trouble!! They will eventually be captured  and then the treasure can be taken. There can be "capturing races" for treasure stones in different parts of the board.
• Treasure stones may not be "declared dead" at the end of the game. To win by capturing a treasure, one must physically take all four of it's liberties. However, if it is obvious that this is going to happen the opponent might as well resign.
• Ko fights are interesting because any Ko threat that could potentially lead to capturing a treasure are very big!  To the regular value of Ko threats - territory or capture - a third type  is a treasure threat.
• It is  important to prevent your opponent  from forming a moyo around a treasure! If he does and you cannot make life inside,  he  will wind up with the treasure!
• Treasure go is serious fighting because regular go is tough enough fighting over territory and to a lesser extent captures but in Treasure Go you are fighting over territory, captures, and treasures at the same time!
• I had originally planned to make all 9 of the treasure stones go on the handicap points but I discovered that making the corner treasures go on the 5-5 points works much better. It enables four handicap stones to go on the customary 4-4 points. Only four handicap stones are needed in treasure go because since they start out attacking a treasure they are more valuable than handicap stones in regular go, and treasure go is for people who are already experienced at regular go, if more than four stones are needed you should not be playing it! Also, placing all the treasures on the handicap spots is ugly makes a window frame pattern. The 5-5 points make the pattern circular with a hub in the middle of the wheel for a much more elegant pattern.
• Last but not least, placing the corner treasures on 5-5 instead of 4-4 enables players to enjoy the the special life and death and eye making properties of the corner that they are used to, the treasure still has an effect on the corner but not as much as it would on 4-4.
• The standard location of the treasure stones, as well as how many of them to use are not written in stone, this is just the standard I have set up. Players should feel free to experiment and either add some remove some or change the location of some, an analogy would be standard chess set up versus Fischer random set up! Although in my opinion standard setup works just fine!