Your opponent has built a large framework, the Go term for a wide area that is surrounded loosely but not yet closed. If it becomes territory, it will be worth a lot. You need to do something about it. The two main choices are to reduce it from outside or to invade it from inside. Picking the wrong one is one of the most common ways games are lost in the middle stage.
This article explains the difference, the typical moves for each, and a simple counting habit that turns a guess into a decision.
The two approaches
A reduction approaches the framework from the edge of it, usually the side facing the centre. The goal is to shrink the area without trying to live deep inside. Reducing stones stay connected to open space or to your own groups, so they are rarely in danger.
An invasion lands inside the framework, usually on the third line or at a corner 3-3 point, and tries to live there. If it succeeds, most of the framework disappears. If it fails, your opponent's area gets even bigger and your stones are captured.
Put simply: reduction is safe and modest; invasion is risky and large.
Typical reducing moves
The classic reducing move is the shoulder hit: a stone placed diagonally above one of your opponent's stones on the third or fourth line, pressing it down toward the edge. Your opponent usually answers by pushing along the edge, which gives them some territory but lets you build a wall facing the centre. Their framework becomes a smaller, lower territory.
Other reductions include a loose approach from the centre, a cap (a stone placed directly above an opposing stone with a gap), or a move on the boundary line where both frameworks meet. What they share is that you are never trapped: you can always run to open space.
Typical invasion moves
Invasions land on the third line between two opposing stones, or at the 3-3 point of a corner that is not yet fully closed. They need enough room to make a base and, ideally, a second option to run. The details are covered in invasion basics.
Count first
The decision between reduction and invasion should come from the score, not from mood. Here is a rough but effective habit:
- Estimate your territory. Count the areas you have more or less secured.
- Estimate your opponent's territory, including the framework as if it becomes theirs. Be generous.
- Add komi to White's side. On this site, komi is 7.5 points.
- Compare.
If, after counting the framework as your opponent's, you are still ahead or close, reduce. You do not need the risk. A reduction that keeps you ahead is enough to win.
If you are clearly behind even before counting the framework fully, invade. A reduction will not close the gap; you need the larger swing that only a successful invasion gives.
This habit is imprecise, and that is fine. It is far better than deciding by fear or by habit.
Other factors
Counting is the main factor, but a few others matter:
- Your own weak groups. If you already have a weak group near the framework, invading adds a second weak group, and your opponent can attack both. Reduce, or first secure the existing group.
- The framework's walls. A framework with a strong wall behind it is hard to invade, because the invasion cannot run. Reduce it instead.
- Thin spots. If your opponent's framework has a cutting point or a gap on the edge, an invasion there may be easier than it looks.
- Timing. A framework that still has only a few loose stones is easier to invade now than it will be in three moves.
The danger of reducing too deeply
A frequent error is a reduction that goes too far inside. It is no longer safe like a reduction, but it is also not placed to live like an invasion. Your opponent attacks it, and you end up with a weak group that makes nothing. When you reduce, stay close enough to open space that you never need to make eyes inside.
The danger of invading when ahead
The mirror error is invading when you do not need to. If you are already winning, an invasion that dies can hand the game to your opponent. Strong players who are ahead often choose the reduction that gives up a few points but removes all risk. There is nothing timid about this; it is correct.
A worked comparison
In this 13×13 sketch, Black's stones along the top form a broad framework. If White counts and finds that the bottom area alone is not enough to win, White needs to invade the top, looking for space on the third line between Black's stones. If the count shows White close even with the top counted as Black's, a reduction from the centre is the calmer choice. The position on the board is the same in both cases; the score decides the move.
How to practise
Play games on 13×13 against the computer on the home page. Each time a framework appears, pause and do the counting habit before choosing. After the game, check whether the choice worked. Over many games, your estimates get faster and more accurate.
When you sign in on the account page, your games are saved, so you can replay the moment of decision later. Try the same judgement against people on the online page, where frameworks are built more deliberately.
Watching the balance of the whole board
The choice between reduction and invasion is really a question about balance. If both players have similar amounts of territory and neither has a weak group, a reduction keeps the balance and lets the game continue calmly. If one player has a clear lead in territory, the other must create a fight somewhere, and an invasion is the tool for that.
Pay attention to your opponent's style, too. Some players build large frameworks deliberately, hoping you will invade so they can attack. Against them, a patient reduction often frustrates the plan. Others build frameworks casually and leave thin spots; against them, an invasion at the thin spot can succeed easily. Reading your opponent's intentions is part of choosing well.
Frequently asked questions
What is a framework in Go?
A wide area loosely surrounded by one player's stones that is not yet solid territory. Go players also call it a moyo.
Is reducing a passive choice?
No. Reducing is often the strongest move when you are ahead or when your own groups are weak. It keeps the lead without risk.
What is a shoulder hit?
A stone placed diagonally next to an opposing stone, pressing it toward the edge while you build toward the centre. It is a classic reducing move.
How accurate does my counting need to be?
Not very. A rough count that tells you whether you are clearly ahead, clearly behind or close is enough to choose.
Can I reduce first and invade later?
Sometimes. A reduction can make the framework thinner, creating a better invasion point later. But each extra move gives your opponent a move too, so do not delay forever.
