Appendix 2. Area Control & The Go Part of GoCaine

This is the area control/combat resolution part of the game.  If you have played Go/Weiqi/Baduk before, then you will already have an idea of the types of surrounding strategies you can use, but pay close attention to some unique aspects here that result from the fact that this is a multiplayer game whereas traditional Go is only a two-player game. 

If you have never played Go, do not despair!  The rules are very simple.  Simple rules, but the strategic options are endless.  Go is very much a game that takes only minutes to learn but a lifetime to master!

In addition if you have questions about Go after reading through this section, an online search for basics of Go or “how to play Go” will yield links to many helpful videos.

The Basics – Capturing An Opponent’s Cells

On your turn you place a cell on an intersection.  Let’s say you are the Yellow player and on your turn you place a cell on this intersection in the Caribbean (Diagram 1). 

Notice that with the exception of edge and corner intersections, every intersection is surrounded by four adjoining intersections (see the red circles in diagram 2).

When empty, these intersections are called liberties.  I find it helpful to think of them as breathing holes.

As long as your cell has at least one liberty (i.e. one empty intersection connected to it), then your cell stays alive.   Presently, in the situation in Diagram 2, the Yellow cell has four liberties.

 Diagram 3 shows a situation where the Yellow cell is threatened by three Green cells.  These three Green cells are occupying three of Yellow’s four liberties.

 

Let’s assume that it is now Green’s turn.  Green puts a cell on Yellow’s remaining liberty (the intersection with the red circle in Diagram 3).  The result is that Yellow is now surrounded and must be removed from the board (Diagrams 4 & 5).

Put any such captured/killed cells in a common pile away from the game board.  Note: unlike in traditional two player Go, in multiplayer GoCaine, the killed/captured cells do not count towards anyone’s score.

Corners & Edges

When you place a cell in a corner, notice that it has only two liberties.  This is the situation facing the Red cell in Diagram 6.
 
A cell on an edge intersection has three liberties.  This is the situation facing the Blue cell in Diagram 6.

Diagram 7 shows a situation in which the Red corner cell has lost both its liberties to White cells and so it must be removed.

Similarly, Black cells have surrounded the Blue cell on the edge.  The Blue cell’s liberties are all now occupied so it must be removed.

Diagram 8 shows the situation after Red has removed their captured corner cell and Blue has removed their captured edge cell.

Capturing Cell Groups

Cells of the same color adjacent to each other form a group.  In effect, when you have cells next to each other, joined by one of the horizontal or vertical lines (i.e. not diagonally), they form one larger living organism.  To capture such a group, opponents must occupy all the liberties of the group.
 
For example, Diagram 9 shows a situation in which two Red cells form a group.  Notice they are in a vulnerable position in the corner and have only three liberties. 

In Diagram 10, Blue cells have occupied Red’s three liberties and so the Red cells must be removed.  

Diagram 11 shows the board after these two Red cells have been removed.

Diagram 12 shows a group of four Red cells.  This group has eight liberties, shown by the small Red circles.

In Diagram 13, Blue has occupied all of the Red group’s liberties and so now the Red cells must be removed.

Internal Liberties (Eyes)

Internal liberties are called eyes.  For defensive purposes you want to build a cell group with two eyes.  As you will see, two-eyed structures are very valuable because they cannot be killed.  It is impossible for opponents to surround such structures because they cannot fill two eyes at the same time.

A structure with only one eye can still be captured because the rule in Go is that the only time you can place a cell into a position where it is automatically surrounded (i.e. into a position that has no liberties) is when, by placing it there, you are taking up the last liberty of an opponent’s group and therefore are capturing your opponent’s cells.

One-Eyed Group/Organism

Diagram 14 shows a group of Red cells that has 11 liberties on the exterior and one internal liberty (the one labelled “eye”).

If someone wants to capture this group, they must first occupy all the external liberties and then lastly place a cell on the eye.  If they try to deploy a cell into the eye before the rest of the liberties were occupied, it would just be a suicide move because whatever cell they place there is immediately surrounded and removed from the game.  Such a suicide move is not allowed. 

Remember, the only time you can place a cell into an eye is if it results in the immediate capture of the group that would otherwise be surrounding it.

In Diagram 15, if Blue were to try to place a cell into Red’s eye before the rest of the liberties are occupied, the Blue cell is instantaneously surrounded and would have to be removed.  That type of suicide move is not allowed.  Blue can only deploy a cell into that eye after the other liberties are occupied.

In Diagram 16, the Red cells are certainly doomed, but Blue still cannot yet deploy a cell into Red’s eye.  There is still one remaining external liberty that must be occupied.

So, Blue places cell B1 (Diagram 17).  Then when Blue’s turn comes by again, Blue deploys B2 into Red’s last liberty, its eye.  In so doing, the Red cells are now immediately surrounded and must be removed. 

The Blue cell at B2 stays there and the Red cells come off (Diagram 18).

Two-Eyed Organism/Group

In Diagram 19 the Red cells have formed a group with two eyes.  Structures with two or more eyes cannot be captured.  Even if you occupy all of the external liberties, you can never capture the group because if you try to place a cell into one of the eyes, the other is still free and in that case the cell you place into the first eye would be immediately killed and removed.  You would just be wasting your cell for no gain at all.

Such is the case in Diagram 20.  If Blue deploys a cell into one of Red’s eyes, the other eye is still open, so Blue’s cell would be destroyed the moment it is placed.  Again, just to reiterate, this would be a nonsensical suicidal move on Blue’s part and is not allowed.

Hence, no matter what Blue or any of the other players do, unless Red mistakenly fills one of its two eyes, this group cannot be captured and will therefore survive until the end of the game (Diagram 21).

Building group structures with two or more eyes is crucial to your defense.  Without such structures, your cells will eventually be surrounded, lose all their liberties/breathing holes and be removed from the game.

Surrounded by Multiple Colors

At some point, multiple players will be involved in the same turf war.  If you have a cell or group of connected cells that loses all of its liberties because multiple players have occupied these spaces, then your units are removed from the board. 

In other words, it does not matter if a cell group’s liberties are all occupied by one opponent or by several opponents.  When you have a cell or group of cells that have lost all of their liberties, then they are immediately removed.

Diagram 22 shows a situation in which Red is in grave danger and has only one remaining liberty (shown by the small red circle).  If any of the players place a cell there, the Red group must be removed.

Let’s assume that it is Yellow’s turn.  Yellow places a cell onto Red’s last liberty (Diagram 23).  The result is all of the Red cells in that group must now be removed.

Kiss The Ring

In traditional Go, players get points for the stones they’ve captured.  In GoCaine nobody keeps the captured cells because the surrounding often involves multiple players.  To provide extra incentive for a  player to complete the capture, GoCaine utilizes a rule I call “Kiss The Ring”. 

With Kiss The Ring, if you place the cell that completes the surrounding of one or more opponents’ cells, you have the option of replacing one of those captured cells with one of your own.  In effect, the opponent’s cell members realize they are otherwise about to die and they strike a deal with you.  They kiss your ring and pledge their loyalty.  You take an unpurchased cell from your supply bag and have it take the place of one of these opponent’s cells.

Above in Diagram 23, I showed a situation in which Yellow played a cell onto Red’s last liberty, resulting in the removal of all of the Red cells in that group.

Immediately following the removal of the Red cells, the board would be as shown in Diagram 24.

However, with the Kiss The Ring rule, upon placing the cell that results in the capture of those Red cells, Yellow now has the option of replacing one of those Red cells with an unpurchased Yellow cell.

Yellow decides that it would be best if it can link up the cell it just placed with the group of three Yellow cells to the north.  Invoking Kiss The Ring, Yellow takes an unpurchased Yellow cell and places it in the gap, thereby connecting the Yellow cells into one group (Diagram 25).

Note that if you are the player who has completed the capture, it is usually beneficial to employ Kiss The Ring, but there are times when it is not wise to do so.  Usually such situations relate to wanting to leave an internal intersection empty in order to create an eye.

This is the situation in Diagram 26.  Assume it is Blue’s turn.  Red is trapped in the corner and has only one liberty remaining (small red circle in diagram).

  

Blue deploys its cell onto that intersection, resulting in the capture of the Red cell (Diagram 27). 

The captured Red cell is removed from the board.  Should Blue now invoke Kiss The Ring and replace that red cell with one of its own?  No, in this case it would not make any sense to do so.  Leaving it empty gives Blue an eye.  As you saw above, it is important for you to build group structures that have two eyes.  So, in this case it is best for Blue not to utilize Kiss The Ring.  Blue leaves the captured intersection empty and in so doing builds an eye (Diagram 28).

 

Capturing Cells from Multiple Opponents at the Same Time

With multiple players all competing for territory, sometimes situations arise in which you have the opportunity to capture cells from several opponents at the same time.

In the example shown in Diagram 29, several players (Yellow, Red, Blue, and White) are all in danger.  They are all sharing the same one liberty. If any one of these players places their own cell onto that intersection, they can wipe out the opposing cells.  Similarly, if either Green or Black places a cell there, then the Yellow, Red, Blue, and White cells would be removed.

Unfortunately for them, it is Green’s turn and Green places a cell (G1) onto the liberty (Diagram 30).  The Yellow, Red, Blue, and White cells must all be removed. 

Green has the option of invoking Kiss The Ring, replacing one of the captured cells with an unpurchased Green cell.  Green chooses to Kiss The Ring on one of the Red cells, thereby connecting it to Green’s larger group.  See Green cell “KTR” in Diagram 31.

 

Note that the Kiss The Ring applies to only one captured cell regardless of how many opponents’ cells are being captured; it does not give Green the ability to replace one cell from each opponent.

Example of an Extended Go Battle between Two Players

If you are not already familiar with traditional Go, reading through this example will give you a sense of how a territory struggle between two players might unfold.  If you are already familiar with Go, the part to pay attention to in this example is toward the end when the Kiss The Ring rule is applied.

Let’s start with the situation shown in Diagram 32 in which it is Red’s turn.  Notice how the Red cell only has one liberty left.  Red wants to save this cell so it must place another cell there and make a larger group to gain more liberties.

 

Remember:  When your cell has all its liberties occupied by opponents, your cell is captured and must be removed. However, when you place a cell next to another one of your cells, they become one living group.

Red places a cell on the empty intersection immediately to the east (R1 in Diagram 33). 

Now, the two Red cells form one living group and have three liberties.  These are shown by the three hollow red circles in Diagram 33.  In order to capture them, Blue has to surround the now growing group of Red cells.

Blue decides to place their next cell on the intersection immediately north of where Red had just placed (B1 in Diagram 34).

Now it is Red’s turn.  Red decides to expand the group, making it harder to surround.  Red places a cell on the intersection immediately to the east (R2 in Diagram 35) thereby creating 3 new liberties.

Blue decides to partially block a potential southward expansion of the Red group by placing cell B2 (Diagram 36).

Red extends northward with R3 (Diagram 37).

Blue cuts off Red’s northward extension by placing cell at B3 (Diagram 38).

Red decides to put some pressure on Blue with R4 (Diagram 39).

Notice now that one of Blue’s cells (B3) is suddenly in danger as it has only two liberties.  Blue also now has a two-cell group that is potentially threatened with two liberties remaining.

Now Blue must consider defensive measures but at the same time wants to put pressure on Red.

Blue decides to aggressively press the attack on Red’s main group with cell placement B4 (Diagram 40).  So as not to clutter the diagram too much, I have not included the small hollow circles to indicate threatened liberties.  By now I’m sure you are familiar enough to spot the liberties yourself.

Red sees that its larger group is potentially in trouble, but also sees that it can put considerable immediate pressure on B3 and potential pressure on B4 by cell placement R5 (Diagram 41).

 

Blue defends against the immediate threat with B5.  This saves cell B3 from immediate capture. (Diagram 42).

Red places R6, thereby threatening B4 with imminent capture (Diagram 43).

In desperation, Blue plays B6 (Diagram 44). 

 

While Blue's move keeps the B4 cell alive for the moment, it is a mistake because now both B4 and B6 are doomed!

Red places cell R7 (Diagram 45).

At this point, Blue should abandon B4 and B6 since they cannot be saved, but the Blue player is a novice and mistakenly deploys cell B7 into a certain death situation (Diagram 46).  What a waste!

Red places cell R8 (Diagram 47) onto the last remaining liberty for those three Blue cells.  Now the three Blue cells must be removed.

The three Blue cells are removed from the board (Diagram 48) and are set aside, out of play for the remainder of the game.

Red now has the option of invoking Kiss The Ring.  Red decides to use Kiss The Ring on the Blue cell that was immediately south of R7.  Red places an unpurchased cell on that intersection (see Red cell designated KTR in Diagram 48).

Beware of Having a False Eye

In having placed the Red KTR cell where it did, Red has created a structure with one eye and one false eye (Diagram 49). 

A false eye is an internal liberty that can still be captured because it involves a cell that is not part of the chain.  In Diagram 49, the R8 cell could still be captured.

Now let’s pretend that Blue’s next cell deployment is B8 (Diagram 50).

Red responds with R9 (also shown in Diagram 50), and in so doing, Red has turned the false eye into a real eye.  Now the overall structure of cells that Red has created has two eyes.  With these two eyes, this structure cannot be surrounded and the Red cells that comprise it shall survive the rest of the game.