While I was in China recently, a local Go player showed me this position. The problem is, how should black play?
A whole board Go problem
The Go game and the players
Here are the game moves that created this Go problem. This is taken from a professional game between Maeda Nobuaki (white) and Kitani Minoru (black). It was played in 1935 during the shin fuseki (new opening) era.
White’s ‘retreat’ to the 3-3 point is usually considered too passive, as it allows black to seal white into the corner with a move at ‘a’. The most ‘normal’ move would be for white to play 14 at ‘a’, dividing black’s two stones and moving his group into the centre. However, normal moves are for normal positions, and in this case white needs to be sensitive to the presence of 8 and 12, making sure they’re used effectively.
In fact, if you look only at the top left quarter of the board, white presently has four stones against black’s two. White 8 and 12 can be viewed as pincers which restrict black’s ability to settle his groups. Seen in that light, white 14 is an aggressive and powerful move (in this position), which prevents black from making an exchange by playing at the 3-3 point himself. Now black has to find a way to manage the situation lightly.
If we consider white’s two pincer stones (8 and 12), 12 at the top looks a bit weaker because it’s inside black’s sphere of influence (black 1, 5 and 11) and has fewer allies nearby than 8. It’s usually more effective to concentrate your attack on the opponent’s weakest area, so black should keep this in mind when thinking about how to play.
A number of possible moves quickly come to mind, the common ideas are marked (a to d above). None of these moves work particularly well though, as we shall see.
The obvious move creates a difficult game
Let’s deal with the most obvious move first, black’s enclosing move at 15. Usually this move would be quite effective, but as we discussed this position is unusual. After white cuts through, black has to defend heavy groups on both sides and white is alive in the corner. White’s stones at ‘a’ and ‘b’ are working efficiently, helping to attack black’s groups. This is a losing battle for black.
To quote Sun Zi’s Art of War, “…a victorious army will not engage the enemy unless it is assured of the necessary conditions for victory, whereas an army destined to defeat rushes into battle in the hope that it will win by luck”. In other words, pick your battles and only choose the fighting variation when a fight is in your interests. Here white welcomes fighting, but black shouldn’t.
Black plays submissively
With that in mind, black needs to play less aggressively and try offer white some sort of trade. An indirect move like black 1 is often good in this kind of scenario – reinforcing black’s group at the top while still aiming to enclose white soon. However, it’s enough for white to just come out with 2 and the best black can do is 3.
Black’s group is now comfortably settled at the top, but his position is so low and he won’t have much territory here. What’s more, once black gives in and plays 3, white’s top centre star point stone becomes very light, basically like a forcing move. I know I just said black shouldn’t fight, but he still has to try harder than this.
The knight’s move isn’t good enough
So perhaps the move to play is the knight’s move? This certainly puts more pressure on white’s single stone at the top and is more positive than the submissive line we just studied. It feels good to attack like this, but you have to think ahead. After black pincers white at 3 white can just choose a simple move like 4 and black has run out of steam.
What’s more, black’s top right corner feels over-concentrated – that means his three stones in the top right are too close together to be efficient.
White has a comfortable game
Of all the moves we considered in our initial diagram, the attachment at 1 creates the most complications. There are many possible variations and I’m not sure what the best continuation for both players is. However, if you think in terms fundamental Go principles, black is trying to attack white’s top centre stone and attaching isn’t usually a good way to do that.
Go theory tells us that we should attack with non-contact moves and defend with contact moves. This is because contact moves often settle and solidify the positions of both players too quickly, making it easy to defend.
Of course at times there are exceptions to all principles, but in this game white can play 2 and 4 (for example) without breaking a sweat and has a fairly easy position.
So what should black do? In the game Kitani (black) came up with a stylish move and a wonderfully creative plan. He found a way to manage the situation flexibly and to put more pressure on white by attacking him on a large scale. This kind of play is exciting!
Thinking about the whole Go board
Black 1 is an unusual move, but in this position it works really well. If white tries to come out at 2, black trades the left side for momentum on the top side. This attack threatens to swallow up white’s single stone whole, putting a lot of pressure on white. A capping play like this is often powerful in large scale attacks.
There is still aji (various possibilities) on the left side, later black has many interesting options (a, b or c to list a few). White can fix this by playing at ‘a’ himself, but if he does so, black would probably play something like ‘d’, which would leave white’s single stone with no escape route and a difficult time making two eyes. Think about how this is different from the diagram earlier, where white could escape easily and black was left over-concentrated.
White can play on the top side now and live, but black will still be happy because the ensuing struggle will probably make black’s two stone enclosure in the top right into a very large and secure territory. It would also be difficult to invade the top right corner right now, because that would let black secure the top side territory.
Professional Go players don’t follow orders
One of the things that makes Go an interesting game is that our opponents are often as smart (or smarter) than we are. In this case, Maeda (white) realised what Kitani’s plan was and found a better variation. One expects nothing less from professional Go players.
After white 1, if black immediately hanes at 12 then white can play all out with a counter hane just below 12. In this game the ladder favours white so this would be a powerful way to cut black. The counter hane is a useful technique to learn for cutting through a two space jump, but it often requires a ladder to work. A discussion of that is probably another entire post in itself.
Presumably Kitani was concerned about this and that’s why he tried to create something with 2… and the rest is history.
The complete game record
If you’re interested in seeing the rest of the game, here it is: