High invasion of mixed three space extension

    Keywords: MiddleGame, Joseki

One of the three-space extension invasions is on the fourth line at the centre of a mixed-height extension.

Table of diagrams
Invasion
Unreasonable: White cuts
White lives too low
White sacrifices
When White has a supporting keima
Another idea with a keima

[Diagram]
Invasion  

W1 is not as common as the invasion at a (see low invasion of mixed three space extension), because Black's response at a will usually connect the two black stones together. Alternatively, Black may choose to attack W1 with b. W1 alone is usually not a good play: usually W1 is used in conjunction with a white stone at c.

[Diagram]
Unreasonable: White cuts  

Trying to cut with W3 is unreasonable. In this diagram, White has achieved nothing. If W7 is played at W8, Black will cut at B7.

[Diagram]
White lives too low  

Trying to live this way is too low for white, and tends to give away too much influence to Black. Later, Black a will capture W1.

[Diagram]
White sacrifices  

Normally the wedge at W3 is too big a sacrifice because it gives Black a ponnuki, but in some specific situations separating black+circle may be worth the sacrifice. In some other situations W7 may be played at a, but Black b can seal the white group in.

[Diagram]
When White has a supporting keima  

With the white+circle stone W1 can be a more severe invasion than W2. When B2 tries to connect, W3 and W5 works in co-ordination with white+circle. Then W1 is placed in an excellent position, at the vital cutting point.

[Diagram]
Another idea with a keima  

Charles In examples from actual pro games, the previous diagram occurs; but other variations do, too. For example W1 here before rescuing the cutting stone white+square.

Also, Black may simply play tenuki after the invasion, treating the whole area lightly.


High invasion of mixed three space extension last edited by PJTraill on November 7, 2018 - 18:15
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