Sky Box
Sky Box (AKA Kill All) is a variant of Go that focuses on sabaki, and life & death.
The game starts with white to play on a board where black has surrounded the edge. White usually starts on the center point (“Tengen”) but can start anywhere.
The objective is for black to kill everything. If white lives anywhere, white wins but if black kills every group, black wins.
It is a useful way to teach white how to play light and quickly make shape to live somewhere (“Sabaki”). It also teaches black how to kill a group when white has made a deep invasion into their moyo.
Strategy
In Go there is a proverb: “Don’t attach to a weak stone”. Attaching to a stone strengthens the stone you attached to because it starts a fight that your opponent has the first move to.
Take for example below, in diagram 1, black starts the fight with 2. Both white 1 and black 2 have 3 liberties each but now white gets the first move in that fight, hane-ing at 3. This is naturally disadvantageous for black and you can see up to 9 that white has used this aji to already start to make eye shape.
To “wrestle” at close quarters is something you do when you’re in trouble but here, white is in black’s area, the wrestling should be done by white.
In diagram 2, black should instead try to gently surround the white group, taking light jabs at white’s shape, like a group of hunters going after a mammoth. To get too close is to be attacked yourself.
Eye Shape
When trying to kill or live, eye shape is important.
In diagram 3, white has 4 groups that have the potential to make eye shape – and therefore – eyes.
A, B, C & D are vital points to either make an eye or the potential to make eyes soon after.
Because your opponent’s vital moves are often your own, A, B, C & D are also vital moves for black, to erase eyes and eye-shape alike.
Imagine that white gets the first move for each group.
A is a solid eye.
B is basically an eye.
C is starting to make an eye but also threatening moves like the triangled point (and many others).
D is very close to being an eye and threatening moves like the 2 triangled points.
These groups all have healthy eye-shape and prospects to make living groups.
In comparison, how do the groups look when black gets there first?
Now, white’s groups have no eyes there and limited prospects to further develop eye space.
What that newfound knowledge, turn your attention back to Diagrams 1 & 2, and notice the difference in eye shape present between the two.
