[Study Group] Essential Life and Death Patterns

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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I think it’s great. My problem is I never have time to just study. I’m dippng in and out all the time but never spending solid time on learning go. So it’s interesting to get a pattern and little explainers in digestible sizes. I only wish I could actually remember things!

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I have had periods of time where I did a fair amount of tsumego study, and it usually precipitated an increase in rank. If I want to do tsumego, I already have resources that I can look at, I’m just not motivated enough right now. So while I think it’s a neat idea, just for me personally I’m not doing tsumego, and if/when I start again, I have other resources I’ll be using.

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This thread is great. I learned about a couple of these shapes here. It’d be more interesting and original if there were a few kyu games linked that had these positions so we see how in-game positions can lead to them but for that you’d need at least a few active contributors that’ll think of this post when they see these positions. I’ll try to be one but no promises.

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Here is a 9x9 that was all about the J shape: https://online-go.com/game/26372488

I analysed it on ogs ai: https://online-go.com/game/26372859

If black didn’t think living in the corner would be enough and wanted to play more actively, perhaps they should have played f8 instead of g8 to make use of the first line aji of the J kill. So, even if you make the shape and die, it’s a good idea to keep in mind what move on the outside can threaten a ko.

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What I think we have are several related fields.

  1. The “essential” life and death patterns, catered to by this thread and also Sensei’s Library.

  2. The “esoteric” life and death patterns, aka tsumego, catered to largely by A tsumego a day keeps the doctor away.

  3. The “regular” shapes, that again don’t immediate devolve into life and death. Discussion of these mainly takes place on Sensei’s Library.

  4. The “esoteric shapes”, that aren’t usually associated with immediate life and death. Those have been getting posted in Share your shapes.

  5. Joseki. These are discussed on OJE and many different threads in the Joseki category.

It seems to me that the boundaries between these five putative zones of discussion are pretty blurry.

For instance, consider this shape that I discussed in Monster seki!

image

If White tenukis now, as in the game I discussed, does his group become 1) an essential life and death pattern and worthy of discussion here?

Or is there no danger to White and it’s still 3) a regular or 4) esoteric shape, or is the idea of White playing away so uncommon that it’s 2) an esoteric life and death pattern?

Or are we still in the realm of 5) joseki?

I like to use three terms to discuss joseki. The joseki sensu stricto are considered the best, then the junseki which are flawed to a varying degree but playable, and finally the noseki which feature one or more real mistakes. I suppose the junseki and noseki are also in the realm of “joseki discussion”.

Perhaps one fruitful searching ground for this thread would be the joseki discussed in The Hurt / Heal Joseki Game: people are clearly interested in this set of joseki, so perhaps the “essential joseki” will lead to “essential life and death patterns” that can be discussed.

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Let’s consider the line-up in H / HJG.

# L&D potential
1 none after diagram
2 abstract
3 none after diagram
5 none after diagram
6 complex
7 doubtful
8 not a lot after diagram
9 none after diagram
11 some
12 some, but verges into joseki
13 not really any after diagram
14 some
15 none after diagram
16 complex
18 abstract
20 some, a little abstract
21 ditto
22 ditto
24 complex
26 not a lot after diagram
29 ditto
30 ditto
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Junseki noseki are confusing words, it would be more a call to some kind of seki for me.
The topic is about patterns so it’s about having answers by classified shapes. It’s not about all kind of life or death problems as per se.
Life and death coming from josekis are added in the perspective that in an effort to memorize a systemic catalogue of basic shapes, you could add a few very common results from josekis. A few very common: aiming to memorize all kind of L&D patterns resulting from josekis is as vain as memorizing the josekis itself.
That’s my guess from the OP (@yebellz )

It would be off topic to take the life or death study by tesujis, placements… Because it’s just not the first idea of the topic.

I read some encouragement to post and discuss more but the fact is that the topic is already quite covered
Book: life and death Ishi press
Online: Sensei library

Some life and death books or puzzles are organized by patterns too so you can build your own analysis.

Ofc there is always place for more discussion.

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There is a book that deals with exactly the topic of the OP - a catalogue of basic common corner shapes and analysis of their life and death status. It is called “All About Life and Death” by Cho Chikun. It comes in two volumes and I have recently started reading volume 2. It starts with the carpenter’s square: first, descended all the way to the first line and with no outside liberties (alive - territory or seki), then with the descent only to the second line and with outside liberties (unsettled - territory or ko), etc.

I quite like the book as it has an index of shapes at the start so you can look up by shape and you can treat it as a problem book (work out the status of the group and the variations in your head before looking at Cho’s analysis) or as an instructional book (just read it and let Cho tell you how it is!). Cho also explains why each move works or doesn’t work and shows lots of good and bad variations for each shape - the Sensei’s library page shows an example for a 3rd line notch shape.

In conclusion, I haven’t got very far through the book yet but IU am enjoying it so far. For anyone interested in this way of learning Go, I think this book might be exactly what you are looking for.

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This is my view.

I agree with bugcat that consideration of various joseki is inextricably linked to consideration of these type of common life and death patterns. Indeed many of these patterns would arise in possible continuations of joseki.

In order to understand why some joseki work, why another move might be needed, or why certain deviations don’t work, one often needs to realize the life and death (such as of an invasion getting cut off) consequences of these common patterns.

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These shapes are really useful. For example, I had a game recently where I could see opponent getting squeezed into L+1 shape (unsettled). It got to the point where I could hane to try to kill but there was a cutting point elsewhere that I read out would have led to a capturing race that I would have lost. So, instead of try and fail to kill, I fix the defect knowing that it was sente as opponent then has to play inside L+1 group to live. Opponent obviously didn’t know about L+1 status because they played elsewhere and I got to kill anyway. My point is, just knowing that L is dead, L+1 is unsettled and L+2 is alive allows you to think in terms of those shapes and statuses and just check edge cases like outside liberties and cutting points with reading, rather than have to read the entire status from scratch - a handy shortcut Indeed :sunglasses:

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Sincerely my knowledge of patterns is limited and I don’t spare time by learning more by heart. If you go through a collection of tsumego and do them again and again you get to assimilate much more patterns as just these basic shapes, I mean sequences which come many times and which help me finding each status.

But some players like to categorize (not me too much) so why not but for me it’s of small help, mildly helpful when faced to life and death.

I trust more the player which has more clear ideas on what happens inside a shape as the one which has more clear ideas on a global status of a shape learned by heart. Ofc you may practice both, it more about how far you push in one direction or the other.

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Notchers!

Shameless promotion of small youtubers continues~

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Here’s a 2003–4 ten position series on joseki related life and death.

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