[Study Group] Essential Life and Death Patterns

Users that have reached the “trust level” of “regular” can turn their own posts into wikis that can be edited by almost everyone (except for new users, I guess to prevent spam). Since you (@Gia) are a “regular”, you can do this as well. Click on the icon that looks like three dots on any of your recent posts, then click on the wrench icon, and you will get the option to turn your post into a wiki.

@bugcat, I’ve been making my more recent posts (unfortunately, it does not seem possible for me to edit or convert older posts into wikis) in this thread wikis in case others wished to add to them, or to correct any mistakes. I’m hoping that this thread would be more of a discussion where we all work through life and death shapes together, but I feel like my presentation style in the older posts might have made things more like a series of lectures. So, I’m trying something different to see if that might increase participation.

Update: thank you to @flovo for helping to convert the older posts in this thread into wikis.

Note: I’ve consolidated a couple of older posts into the original post.

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Does this work?

I don’t think so.

42, 21, 12 kills. 13 and 41 are miai to prevent black from forming a 2nd eye.

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If it’s black to play, I’m fairly confident that A17 lives. I’m not sure what the best result white can get if it’s white to play.

image

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With white to play, does this kill?

No, and I’m fairly sure the refutation is the same.

image

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I already knew the status of the tripod group but I had to check Sensei’s for the details.

How do we do spoilers btw?

[details="Title of spoiler"]
You are spoiled
[/details]

Will result in >

Title of spoiler

You are spoiled

There is also a convenient shortcut under the cog button (which is not intuitive at all, I agree)
Untitled-1

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I know about the summary function, but I can’t use that in the middle of a line of text. I tried and it didn’t work.

Well, then just don’t? :smiley: I am sorry I am not sure what the question is then. Yes, it is impossible to use in the middle of the line, and there is no way to work around it (that I know of).

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Something < spoiler>like this< /spoiler> doesn’t work?

Without the spaces. That’s how I’ve always done it in Disqus.

Edit: it’s also supposed to show a blur option where the poll is, but I usually use the tag, so I don’t remember exactly, but my guess would be it needs to be turned on by an admin.

Turn on dark theme!!!

FIFY…
image

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I want to share some thoughts about why are these patterns important for progress (more so than other life-and-death problems)?

  1. They are the result of typical corner invasion sequences. You still have to learn the invasion sequence but it helps to know the result is alive at a glance. More subtly, you know the standard shapes and look for sequences that build them.
  2. They are essential for more advanced life-and-death. When a sequence ends up with a group you know is dead, you can stop reading early and discard the sequence.

Simple example : take a L+1 group. If you play hane on the “+1” side, you get a L group which is dead. Problem solved.
If I have the time, I’ll share a few such sequences for 1. later.

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L group in actual play:

Look at the bottom right group starting at move 9. My opponent played for the “natural” defending moves which end in a L-group, probably not recognising it was dead, and giving me an easy game.

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Shape 9: One-Space Notchers

Not really a single shape, but rather a family of shapes, which are in turn part of an even larger family of shapes. See also the Table of Notchers (link posted by @bugcat earlier).

Status?

5-notch

6-notch

Spoiler Proverb

“Four die, Seven live”
or, alternatively,
“Five and Six are unsettled”

Note: weaknesses and liberties also affect the status

Status in the corner?

corner-a

corner-b

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Shape 10: Hovercraft

This is a common shape that could arise after a 3-3 invasion

hovercraft

Sensei’s library: https://senseis.xmp.net/?Hovercraft
See also: https://senseis.xmp.net/?JosekiRelatedLifeAndDeathExample2

Haylee’s video (as shared above in the first post) covers the related shape of “Hovercraft with descent” as shape number 5 in her list.

descent

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Shape 11: The J Group

Recognizing the life or death of this shape is also important when dealing with 3-3 invasions.

Status?

f5e7d4173ba7834116bd7c1144017907

Sensei’s library: https://senseis.xmp.net/?JGroups

Status with the hane?

3b3f2aa4fb5f70eb12674be73946b595

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I was wondering if there was any interest in reviving this topic.

I had always hoped that it would become a more of an interactive discussion (and not dominated by just my posts), but much of the content wound up just being me posting summaries, instead of questions and back-and-forth discussion about various corner shapes. Maybe this format for a study group is not what most people like? Here are some general questions:

  1. Do you find the content of the thread useful?
  2. What do you think about the format?
  3. Do you recommend any changes?
  4. How to encourage more discussion?

Finally, to hopefully encourage some more participation:

  • What are some life and death shapes that you want to explore?
  • Any questions about the shapes discussed above?
  • Please share various Go problems
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Honestly, for me it’s nothing very new, u have all these in some books that i never read from beginning to the end.
When i meet something similar in my game (it’s rare but happen) , i go check by myself and when i do life and death, i like more all kind of shapes mixed.
Well, my taste. I still hope some other players will appreciate more your effort to compile here these shapes as me.

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Answer:

For the 1st thing, play E1 to live. This is a simple case of miai, where if white plays at one point, black plays at the other. In this example, the miais are at C1 and G1. Notice that if white plays G1, black can play C1, and vice versa. This is unsettled.
For the second thing, again, play E1 to live. (Same explanation as above). This is unsettled.
For the third thing, play B1, C1, D1, or E1 to live. White cannot make a ko, so it black is alive.
For the fourth thing, black is alive. If white plays E1, black plays C1. If white plays C1, black plays B1. If white plays B1, black plays C1, and if white plays D1, black plays E1.

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