Keima Side Connection / Discussion

Reference diagram  

Why the cut is impossible

aLegendWai: I am going to show all possible attempts to cut. If you are unsure why Keima watari can ensure the connection. It is worth reading on. I will show both the correct and wrong responses. So weaker players can avoid the wrong ones.

Attempt to cut 1 - correct response  

It is the best B can do. is an example of dropping back. See dropping back for details.

Attempt to cut 2 - correct response  

If Black a, then White b.
If Black c, then White d.
If Black d, then White c.

Attempt to cut 3 - wrong response (B)  

The purpose of is to try to block B's connection by a ladder. However there's another sure-fire way to ensure the connection.

Note: W cannot capture by a net. It is because cannot played at "a".

Example from pro game  

In the third game of the 2003 Kisei, Yamashita Keigo plays 1, applying a variant of this tesuji. a and b are now miai for the connection. If White 1 at a, ...

Example from pro game  

... Black forces and captures three stones.

Ladder(s)?  

Charles Matthews I see several possible ladders here for White, after White 1 to White 5. If Black 6 connects, White can get parallel ladders with White a, Black b, and then White c, or White d, Black c, White e - and there's more where that came from. Obviously since the marked white stones have just two liberties, a net is a failure.

Or White 1 at 2, naturally, but isn't squeezing better style?

So - all these ladders were broken?

Dieter:Sorry. All ladders work for White. White is very strong in the center. So in this case, her move works. Bad example. To continue: It is beyond my capability to judge the global position for the different choices you mention, I just wanted to point out the local issue.

JanRamon: If white relies on ladders, there's always the Aji of ladder breakers, and any attempt of the black stones to escape is sente because the three white stones can be captured. So in the game white just safely connects and takes territory while blacks center stones struggle to live.

Ladders unnecessary  

White does not need the ladders at all. Even if all ladders to the lower right are broken, white can capture the black stones easily using this sequence. This is better for white than the sequence in the previous diagrams, because he does not have the ladder breakers to worry about - Andre Engels

And the next question is ...  

Charles Matthews So, now I'd like to ask what happens if Black plays 1 here?

And the next question is ...  

? Dieter

And the next question is ...  

? Dieter

Better?  

Charles I think White 2 must be correct, but it takes a little reading. The point is probably that Black a can be answered by White b.

Andre Engels: Yes, Dieter's second answer and Charles's answer are correct. After white 2, c and d in Charles's answer are mi-ai, both ensuring a connection. Dieter's first answer is riskier and leaves more aji, for example note that a black move at 4 in that diagram is sente against the three stones below.

Better ?  

I think I still choose the shape move, though it loses territory. Dieter

Tactical point  

Charles Just to explain a hidden tactic: Black 4 here prevents an immediate atari by White, and Black 6 creates a ko. This is big for Black, but not necessarily enjoyable.

Example from pro game  

dnerra: I'd suggest this line as a refutation of White 1. Unless white wants to give up on the stones on the left, she has to play 3 (ugh), 5 (oh dear) and 7 (horrible as an exchange with 6). Compared to the game move, white has a little more territory, but black got two full moves on the outside.

(And I don't think White 3 at 4 can lead to a good result if Black pushes at a.)

imagist: at seems fine to me. Black a is just pushing from behind, and since it was earlier noted that white is strong in the center, this seems like a nice way for white to create a center moyo by attacking a weak group.

IGOMN390 5d+ (w) vs. ita0929 5d (b)  

There is some pushing going on. connects along the side with the keima side connection. The nice thing about this connection is that a future move by white at a is not sente to break the connection of the black stones on the edge. You might say that black "over connects" his stones on the edge to eliminate a potentially useful forcing play for white.
In contrast, after this connection...

more bad aji for black here  

Now is forcing as white threatens the a through e sequence.