Anyone willing to speculate about the origin of ko? Is it perhaps natural to think that in the ancient beginnings of go that there was no rule against immediate recapture - that, in a sense, it could have been seen simply as a defensive measure, along the lines of telling your opponent, "hey, you cannot take me here, since I can take you right back." - in this way the onus would be on the initiator of the ko to play elsewhere? Chess has a similar situation with threefold repetition: the players come to an impasse, neither player wanting to budge on their choice of moves (though sometimes they do, and the game continues) and the game ends in a draw. Thoughts?

Ancient alien civilization.

I sometimes wonder how ancient peoples found out about the intricacies of the game. You know, in the years directly after its creation.

Trial and error most likely

It happenend slowly, I expect. IIRC, there is an ancient text that tells of a remarkable player who could replay a whole game from memory. Now that is commonplace among pros. Correct play in the Carpenter's Square was unknown for centuries. A number of very ancient joseki appear quite inefficient to modern eyes.

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The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Surely you have heard the story of the rotten axe. There is reason to believe that the game in the story was played before retaking ko was disallowed. The descendents of the participants insisted on the rule change so that they would not lose any more family members.

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Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).

I'm looking at the page on carpenter's square - do you mean correct play to make a ko as white or do you mean to live as black, because that vital point seems incredibly obvious. Also, do you have examples of ancient joseki?


Who can imagine the ancient world of Go where the strongest players are 20k?

The vital point isn't the hard part.



I know nothing about the historical origins of ko, but it seems like a natural development once people began to see recurring captures that would decide the winner of the game.

The details of the carpenter's square and its variants are extremely difficult. As you probably guessed, all the difficulty comes from the variations where the attacker moves first, rather than the defender.
* What is best play by in the normal case to make ko?
* What are the refutations of common mistakes by either side?
* How does best play vary with the number of outside liberties and the ko threat situation on the rest of the board?
* How about alternate edge configurations including "legs", descents, hanes, and escape threats?
* Also, what about the various "weak carpenter square" variants where the 4-4 corner stone is missing or is occupied by the opponent, along with all the accompanying variant edge configurations?

For most "basic corner groups" and their variants, these questions aren't too hard to answer if you're generally familiar with the shape. For the carpenter's square, I'd guess that most dan players still don't understand the shape, in the sense of knowing or being able to quickly figure out answers to the above questions.

The attack on the 2-1 was originally believed to kill without ko. See http://senseis.xmp.net/?CarpentersSquareWrongAttack



No, but if you look at the very ancient games in the GoGOD collection, some of those lines of play that produce clumps of stones were actually joseki.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

I find that rather strange as I can do that, but I don't see how that ability of mine is influenced by me standing on the shoulder of giants with the combined development of go theory over the centuries; whereas something like my understanding of opening theory obviously is.

It says in SL that the correct solution was not known until the 1300s. Where is the evidence for this? There were no problem books before then?

I imagine this is a garbled account based on the fact that the Zhaixingpu, which is an old book but nowhere near as old as Xuanxuan Qijing, does have the erroneous move. But modern books also have mistakes and we don't disparage the ancients on that basis.

I have had a quick look into non-standard carpenter shapes and the complexity of variations explodes, and perpetual kos can occur. Maybe computers are "familiar" with it, but I doubt it. Carpenter square really needs meticulous functional study. Pure, sufficient reading of difficult shapes needs something like 200 or 300 variations, according to my current estimate, but IMO reversions should allow a decrement of the reading volume. I will study it more carefully later.

There's this: http://www.go4go.net/go/carpenter_square

Recalling a game is not hard, but it does take practice. And it can be surprising what earlier generations did not do. Just look at the development of weight training for athletes in the 20th century. For instance: https://twitter.com/gruber/status/459139851154374658.

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Occupy Babel!

As for the OP, I sometimes wonder what a GO variant in which no zero liberty group was allowed _ever_ would be like.
I mean removing the rule that a group of zero liberties can be created if it captures another group.

If you would not be allowed to capture by creating a zero liberty group then:
- there would be no KO
- one eye was enough to live
- false eyes would become true eyes
- a lot more seki would appear

What I wonder: would it be a game way more simple or almost equally complex?