There is an old Go proverb that says the fight begins with a cut. Almost every serious battle in a game can be traced back to a moment where one player could separate two groups of the other player's stones, and did. If you understand cutting and connecting, you understand where fights come from and how to avoid the ones you do not want.
What a cut is
Stones of the same colour are connected when they touch along the lines, horizontally or vertically. Diagonal stones are not connected. A cutting point is an empty point where, if your opponent plays there, two of your groups become separated.
A cut is the move that takes that point. After a cut, you have two groups instead of one, and each has to take care of itself. Two weak groups are much harder to look after than one strong group, which is why cuts lead to fights.
Spotting cutting points
Look for these shapes in your own stones:
- Two stones diagonal to each other with both of the connecting points empty. Your opponent can play one and cut if the other is also theirs or will be.
- A one-point jump (two stones on the same line with one empty point between them). It cannot be cut directly, but it can be pushed through if the opponent has stones nearby.
- A knight's move (like a chess knight). It can be cut with two moves, which makes it thin in a fight.
- A two-point jump with the opponent's stones close by. It is very easy to separate.
The more of these loose shapes you have near your opponent's stones, the more cutting points they have to choose from.
Ways to connect
When your opponent threatens to cut, you have several ways to connect, each with its own character.
- Solid connection. Place a stone directly on the cutting point. It cannot be cut again and has no weaknesses. The price is that it is slow and adds nothing new.
- Hanging connection. Place a stone diagonally so that if your opponent plays on the cutting point, their stone is immediately in atari and can be captured. It covers the cut and is more active, but it can leave a weakness if your opponent gains a ko threat or a forcing move later.
- Bamboo joint. Two pairs of stones side by side with a gap between them. It cannot be cut, because whichever point your opponent takes, you take the other. It is strong and efficient.
- Virtual connection. Stones that are not connected yet but that your opponent cannot separate without losing something. A one-point jump near the edge is often virtually connected.
Knowing these lets you choose the connection that fits the moment: solid when you need no weakness at all, hanging when you want efficiency, bamboo joint when you are extending under pressure.
When to connect
Connect when:
- The cut would create two weak groups, and you cannot afford to defend both.
- Your opponent has strong stones nearby that would make the fight go their way.
- You are ahead and want to remove every source of trouble.
A solid connection can look slow, but a group with no cutting points is a group you do not need to think about for the rest of the game. That is worth a move.
When to let them cut
Sometimes the best answer to a cutting threat is to leave it. If you play somewhere bigger, and your opponent cuts, you might be able to:
- Sacrifice the smaller group while the bigger one becomes strong.
- Counter-cut, splitting your opponent's stones as well, so both sides have weak groups but yours are closer to safety.
- Capture the cutting stone because the cut is not as strong as it looks.
Reading tells you which of these works. If you cannot read it out, connecting is usually safer.
When to cut
Cut when:
- The cut separates two opponent groups that are both weak. Now they face a double problem.
- Your stones around the cut are stronger than theirs, so you will win the fight.
- The cut forces your opponent to spend moves saving groups, giving you the initiative.
Do not cut just because you can. Cutting when your own stones are weaker than your opponent's creates a fight you will lose. A cut is a declaration of war, and you should have more soldiers nearby than they do.
A simple atari after a cut
Small positions like this come up after cuts all the time. The cutting stone is often weak and can be captured, or the stones it cut become the weak ones. Counting liberties for every stone involved in a cut is the fastest way to know which side the fight favours.
Shape and cutting
Good shape is largely about avoiding unnecessary cutting points. Two habits help:
- Avoid empty triangles (three stones forming an L with the fourth point empty). They waste a move and still leave weaknesses around them.
- Prefer shapes with no cuts when extending near your opponent: the bamboo joint and solid extensions are safer than long jumps.
Strong players do not avoid all cutting points; that would be too slow. They leave cuts only where they have read that the cut does not work, or where they have a plan if it happens.
Practice
Watch for cutting points in every game. Before you play a move, ask: "Where can my opponent cut me?" and "Where can I cut them?" This double check, repeated for a few weeks, makes a large difference.
Short games against the computer on the home page are good practice; the lower levels often leave cutting points open, so you can learn when a cut works. Then play people on the online page, and replay games from your account page to find the cuts you missed. More on the fights that follow: attacking weak groups and the ladder and the net.
Frequently asked questions
Are diagonal stones connected?
No. Only stones touching along the lines are connected. Diagonal stones can be cut if both connecting points are taken.
What is a hanging connection?
A move that protects a cutting point by making sure any stone played there would be in atari immediately.
Is a solid connection too slow?
Sometimes, but it has no weaknesses. When the surrounding fight is dangerous, slow and safe is often correct.
Should I always cut when I can?
No. Cut only when your stones nearby are stronger, or when the cut separates two weak groups.
What is an empty triangle?
A clumsy shape of three stones in an L with the fourth point empty. It usually wastes a move.
