Forum for Tiger's mouth
Tiger Chain [#1639]
This shape came up in a game recently:
![[Diagram]](diagrams/2/224fa3724b3175cb55ab7de6b713cc9a.png)
When I formed it with the marked stone I thought it was a good shape, but had a vague feeling that I'd played it before and it had proved to be bad. I guess I'm asking, does this shape form often? Is it worth having info on it? I guess if Black were to peek into all the mouths it could become a horrible dango... avoidable?
![[Diagram]](diagrams/36/e99a398570fbc9b2c43ce8d8709fa9b5.png)
fractic: Why not play 
here. You were probably worried about the peep at 
but with 
in place and no black stone at 
there isn't much to worry about.
![[Diagram]](diagrams/28/fda4af96cc2676c3a190ffddbcbe8534.png)
fractic: Suppose Black peeps with 
. If the shape is close enough to the lower right then White can probably kill that stone with or .
![[Diagram]](diagrams/50/6ab43d99308638f095773723d631bc0c.png)
fractic: If White is stronger here or close to the top side then 
could be very effective. If Black breaks out with 
-
for example then
![[Diagram]](diagrams/21/90af787de122a9a97267d3db92bad2dd.png)
fractic: If White can handle the cut at then Black shouldn't play this way and just abandon his peeping stone.
Well, I didn't want to discuss my game so much as I wanted to know more about this shape (good/bad/strengths/weaknesses):
![[Diagram]](diagrams/45/97a258c117a34f23e7c1d6176301b19f.png)
![[Diagram]](diagrams/14/c80f2d2809618cbfa5d78fff8585178d.png)
![[Diagram]](diagrams/11/3ee435233b89f941d6fee0d1349551da.png)
![[Diagram]](diagrams/49/88dfd649757307c2d238ebbff3c57e2f.png)
While the discussion is not made specific to a game, discussion of a shape has to be made in conjunction to the surrounding stones.
For example, the move in both diagrams really are not the same.
![[Diagram]](diagrams/4/e457f65fb69744b2ae37c10b13d5e561.png)
![[Diagram]](diagrams/24/5a8184e28c6039f601615270d293594f.png)
![[Diagram]](diagrams/45/8f5dc9fdf3ebff57f7e8ecd865195fce.png)
The issue of efficiency was already raised by unkx80. Shapewise, there is the fundamental weakness of the diagonal, compared to straight? development. Although this diagram is artifical, it displays rather nicely the weak aspect of the diagonal.
Both have used the same number of stones. Black can cut White all over the place, while Black is strongly connected.
Actually my point is not efficiency, although it is also a important consideration.
My point is much simpler: whether a "shape" is good or not depends strongly on the presence or absence of nearby stones of either colour. These cannot be omitted for a meaningful discussion. Looking back at his diagrams again, these are really two different beasts, even when the difference is only the 
stone.
![[Diagram]](diagrams/22/3b2643cb17ba1df169ed014269ad4aa7.png)
![[Diagram]](diagrams/42/af0c19e6917c7e718450fcb1c05e3c46.png)
![[Diagram]](diagrams/15/64aacb5fce28e61c564e43956d7dee8b.png)
Shape wise, such a chain of tiger mouth can be used to quickly make eyeshape, eg:
![[Diagram]](diagrams/16/14aa04376f6f20162114ff3a96f6a050.png)
The others have already given good comments. I'll just add a bit more.
![[Diagram]](diagrams/10/934fbee35ed4e6b9682d2cddcb8b5b95.png)
![[Diagram]](diagrams/29/03de393ddd3c8c2c77ace6e67ba9bf27.png)
Roughly the same effect can be obtained by a series of one space jumps, which uses up to 50% less stones. This is more efficient while maintaining the connection. For this reason one space jumps is seen a lot in games instead of tiger mouths chained together.
![[Diagram]](diagrams/29/c825db96e879e5842b83196257ed85b6.png)
In this case, the stone reeks of the weak player's diagonal. The attachment at a would usually be a good move for Black, highlighting White's poor shape.
In the game you provided, the chain of tiger mouths came about because you wanted to block your opponent's entry into your territory. Incidentally, this shape allowed you to secure the territory. So I have no negative comments on it.
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