Xray Monkey Jump
This isn't a standard name, but the shape is common enough that I think it deserves a name -- xela
In this diagram, black would like to play the monkey jump at a, but it looks like the marked white stone is in the way. However, black a still works, because white is short of liberties. I call this the x-ray monkey jump, because black can see through an apparently solid obstacle. (The clamp at b is always an option in this position, but a is usually the better move if it works.)
This choice of
is more complicated, but after
, if white tries to block with
then again black can capture some stones. Note that
at a also works, but this choice of
is usually better. If white plays elsewhere at this point, then later threatens to rescue the stones as a ko threat, then this choice of
minimises white's possible gain, while black a instead makes for a bigger ko threat.
When white has an extra liberty at or near a, or when the marked black stone is missing, usually this means that the x-ray monkey jump fails: white can block safely. But depending on the nearby shape, there is potential for ko: see the next two diagrams.
In this position, black x-rays in from the marked stone on the right. Because of the liberty at a,
can't connect out, but black can make a ko for the life of the white group.
See also:
- oki wants ikken tobi, playing a defensive move one space across from the x-ray monkey jump.
- Gokyo Shumyo, Section 2, Problem 24: there are other ways to create shortage of liberties in this shape!
![[Diagram]](../../diagrams/16/30890ed9f010fdc29dce565c17ba3f3c.png)
![[Diagram]](../../diagrams/47/610c148c434d09a57a6bfedaa643ee30.png)
![[Diagram]](../../diagrams/51/557ea92f6fda5009e280346a71c75ffc.png)
![[Diagram]](../../diagrams/14/1f3d2a1496ee47171b1651a20f65e84d.png)
![[Diagram]](../../diagrams/2/a1cbd9adceceede6837830eb998cc894.png)
![[Diagram]](../../diagrams/28/37fe3bd9d57daa8d6ff5c6866012af89.png)
![[Diagram]](../../diagrams/40/5fc610983694f4b9fb8d8f3781704f7c.png)
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