Welcome to Part 3 of our tutorial for the game of Go.
This part will wrap up the introductory-level tutorials
and is geared towards those who have tried Go out a bit
and decided to delve deeper into the game.
The goal in this part is to provide you with the key terminology and concepts you'll need
to understand more about what you're seeing on the board,
participate in Go discussions, and
understand Go lectures and study materials.
Part 3 will work a little differently from the first two parts in that we'll briefly touch on a variety of topics -
you can use your pause button if you want to look at something longer -
and even with that we had to break Part 3 into two sections for time reasons;
here in Part 3a we'll cover terminology.
"Atari" is the condition where a stone or group has only one liberty left
and could be captured on the opponent's next move unless something is done to save it.
"Double atari" occurs when two groups are put into atari with a single move.
Generally only one or the other can be saved.
"Group" is a word you'll hear used in two slightly different ways;
usually it's used to refer to a set of stones that are close enough to each other that they're working together locally.
These stones constitute a group even though they aren't actually touching.
When we're discussing liberties and capture, however,
sometimes we switch focus so that "group" refers to stones that are continuously linked
and so are counted together for liberty purposes.
Context will usually make it clear which one is meant at the moment.
"Shape" is the spatial arrangement of the stones in a group.
Good shape gives the group the maximum effectiveness for the number of stones it contains,
whereas bad shape leaves weaknesses or inefficiencies.
Good shape is very dependent on the situation, but generally it's good shape for stones in a group
to be spread out in two dimensions as in the right group here.
This way they can simultaneously claim territory, make space for eyes and reinforce each other.
A one-dimensional arrangement with the same number of stones is usually less useful.
A "base" is a special case of good shape formed along the side of the board.
If black plays near this stone, it's pretty important for white to make a base here,
forming the two-dimensional shape we already mentioned.
This is not yet enough room for two eyes, but it's an important beginning.
If black gets the chance to play here, it's a good move to play a "pincer",
which denies white a base and severely damages the usefulness of the white stone.
"Moyo" literally means "framework". It's similar to making a two-dimensional shape
but it's on a larger scale, involving stones that are too far apart to be considered group.
In this example, black has a moyo that begins to make a claim on the shaded points,
a claim that comes from the arrangement of the stones rather than having to play extra stones.
"Joseki" are standard sequences for common positions
which been carefully worked out by the experts to give an even result for both sides.
The result is even because it reflects optimal play by both sides, not because the players are just being sporting.
Joseki generally apply to opening sequences in the corners,
but occasionally you'll find joseki for common positions that arise in other phases of the game.
Joseki can be quite complex, but may be as simple as this sequence:
If black opens on the star point white has a good approach here.
the most standard, if somewhat counter-intuitive, response for black is here,
after which white settles on this side.
In-depth Joseki study is pretty advanced, but even beginners can benefit from picking up some simple sequences like this.
At least it provides some basically sound ways to play and can't go too wrong.
"Aji" is the latent potential in a particular situation, usually
used to refer to the residual usefulness left him dead stones.
In this example, notice that the marked white
stone is thoroughly dead.
If it's black's turn, we know from previous
life and death examples that
they would like to play here, to prevent the
white group from getting two eyes.
But in this case it doesn't work because white
has another way out, namely to atari here.
When black saves those stones, white can in turn
capture these stones, saving the corner group.
If the "dead" white stone had not been present, white
would not be able to get out because the atari here
still gives black time to kill the group directly.
There are many ways of using the aji left in stones;
sometimes in the process, dead stones even come back to life.
A "Tesuji" is a move that is not normal but is
an effective technique in a given situation.
For instance, in this position white is threatening to
connect his group out via triangle
and our normal move would be to block here.
But if we do that then white can just connect
to make the group alive by itself.
Here black has a tesuji called the "throw in."
This is not what you'd usually call a normal move.
We don't normally play a stone where it's already in
atari and can be immediately captured.
But in this situation it's just what black needs.
If white captures it, white's own stone
fills in the space for the second eye.
What looks like an empty space here is a "false eye";
it's actually the space that white will need to connect.
So the throw-in tesuji has allowed black to kill the white group.
"Sente" roughly means "having the initiative."
A sente move contains a threat that pretty much requires your opponent to respond to it,
meaning that the initiative comes back to you on the next play.
Its opposite is "Gote."
A gote move does not force a response, and leaves your opponent free to carry out their own plans.
We can also say that a player "has sente" on a particular move, or does not,
meaning having the freedom to choose where to play next rather than being forced into a response.
Keeping sente is a key element of play and we'll see it come up in different ways.
A "fight" describes when groups on both sides have to contend to live.
In this case black has the option of just keeping things simple by connecting the stones into one strong group.
But there's also the option of playing here to keep white's stones apart.
Now white keeps black from connecting these stones.
Now black has three groups to manage, but so does white, and a fight has started.
Whether it was a good idea for black to start the fight depends on the overall situation.
A "capturing race" is a particular type of fight were two adjacent, opposing groups have both been cut off
like the two sets of three stones in the center here.
It becomes a showdown where whichever one captures the other will live.
This often has implications beyond just the two groups vying for liberies.
You can easily imagine that one or both of the outside groups might be depending on the contested area to make eyes.
And in a capturing race, "Seki" is an odd sort of position that you sometimes encounter at the end
where both groups end up living, only because they both run out of liberties and neither can capture the other.
This position is very similar to the capturing race example, but it turns into seki.
Black can't play in either one of the empty spots to try and capture white
because it would reduce black to one liberty and white would just capture.
White's in the same situation so both groups stay alive in seki.
A "ladder" is a pattern that comes up often.
You can generally recognize it as when a stone or group that's in atari can escape,
but, in escaping, ends up with only two liberties so that it can be put back into atari in the next move.
If there's no help around, continuing a ladder is futile because the threatened group eventually runs out of space,
by running into an opposing stone or reaching the edge of the board, and then the whole thing gets captured.
If there is a friendly position the path, however, it may serve as a "ladder break" -
sometimes even a single stone will do -
if the stones in the ladder can buy even one extra liberty, the ladder no longer works;
all of the laddering stones now become double-atari points and the laddered stones can get out.
So when a ladder situation comes up in a game, you need to read along the path
to see if the ladder's good for white or good for black.
A "net" is a pattern that can sometimes get a cleaner capture than a latter.
In this example, black could start a ladder in either direction, but white has a ladder break that works for both sides.
If black just plays this net, however, the stone simply can't get out.
"Connect-and-die" is a pattern where a group that's in atari can connect to other stones,
but the resulting group is still in atari and can be captured.
To capture two blacks stones, white only needs to play here;
although the stones could connect, it would only mean that white gets to capture more.
Here's where we'll break part three. When you're ready to move on to concepts, select Part 3b.