Go Graded Problems for Beginners - Vol. 1 - 2 Questions

These are both easy endgame problems from the first section of the book:
1-

I don’t understand why move 1 is considered a necessary defensive move now for black and likewise for white at point 2. These moves only become necessary once the opponent advances along the first line toward the stone of opposite color, isn’t it?

2 -

There’s an errata list on Sensei’s and it says it should be 3 dead white stones and not 5, why is that? Is it considering the 2 white stones on the right side are not dead?

About the same problem, that’s the solution:

Can you infer what’s being said about the black stones? They’re totally dead for me.

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For 1.
If black plays at 1, they are playing inside their own territory losing a point. Look at the below image for white playing 1:


Here black responds with 2, inside their own territory, white plays 3 which does not lose white a point, this forces black to capture with 4. In this scenario, black has played twice inside their own territory, rather than just once. If black responds to white 1 with black 4, rather than black 2, they lose the group.

Edit: Ignore the ‘5’ on the left of the image, I don’t know how I put that there.

For 2.
I’m not entirely sure why sensei says only 3 are dead.
Edit: The webpage says it’s specifically for "ISBN 4-8182-0228-2, ‘Second printing July 1990’ ". Can you check which printing you have? Maybe there was an error in the image of the book that has since been corrected?

For 3.

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1 - Black plays twice inside his own territory, but gains one point for the capture, so it’s the same in the end, isn’t it? Which is the same as I see on the left side, what can black do in this moment to force white receive less points?

2 - Oh, mine is “First Printing March 1985”. It makes sense that the error would be in my edition, so I don’t know ;(

3 - Thanks! He just confirms that the stones are dead and there’s nothing else to do.

1 - This is a good point, maybe I need some coffee :slight_smile:

2 - your image looks like what I have in my book, so I’m not sure what the people at sensei’s library think is wrong?

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My guess is that it is to prevent mistakes when filling in dame. I think it’s good practice to play such moves before dame because players are often on autopilot at the end of the game. In 2002, professional Go player Ryu Shikun lost a won game (game 5 of the 26th Kisei) after missing an atari on his stones during the dame-filling stage and filling another dame instead.

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I completely agree. It’s not necessary now, but it’s good habit.
(This being said, the book doesn’t say you have to play them now; it says you have to play them before playing the last moves of the game)

I’d like to add the point that recognising those defensive necessities in advance will allow you to substract them when you are estimating how much territory you have precisely. It is a useful skill to have for the future.

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I’ve deleted that part of the Sensei’s library page. You are right: all five white stones are dead.

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Would you say it’s better to make these defensive moves rather than the attacking ones? At this point in this simple game, I guess it makes no difference (black plays two points to the right of “2”, for example), but is this a good practice in general? I was once shown a situation where a critical defensive move wasn’t made and then when a dame was filled, suddenly a weakness appeared and an invasion became possible, that’s what you’re talking about?

It depends on what you call an attacking move.
If there are moves on the board that are worth points, then playing a defensive move that is not immediately necessary loses you points. So you shoudn’t do it.

As soon as there is nothing left worth points (dame phase), as is the book, my recommendation is that you find and play all defensive moves before actually filling the dame. So, in the book situation, I recommend that Black plays 1 before playing at the right of 2, as a matter of good habit.

I was once shown a situation where a critical defensive move wasn’t made and then when a
dame was filled, suddenly a weakness appeared and an invasion became possible, that’s what > you’re talking about?

Exactly. The final result is the same in any case.

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In general, if you’re unsure whether or not you need to defend, then I’d say don’t do it (unless you’re playing a serious tournament game and you know you’re well ahead). Once in a while you’ll misjudge something, and you’ll have what you might call a disaster, or you might call it a good learning experience. Over time, your play will improve.

If you get into the habit of defending unnecessarily, it’s a lot harder to figure out when your judgement was wrong, and games will slip away from you without you clearly seeing why.

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But you still maintain the “defend everything before the dames”, right?

It depends entirely whether the defence is necessary. Playing unnecessary defense before dame will cost you points in most rulesets.

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Now, I’m getting mixed opinions :laughing: As a rule of thumb, should I do it or not? As you can see, the beginner’s book is trying to ingrain the habit of doing it (make the defensive moves before dames). I’m sure there are situations where this is incorrect (nothing is absolute in Go), but just a point of departure, something to be aware that you’re probably right, before acquiring better reading skills …

Mixed opinions?

I do not think you were getting mixed opinions: all agree that you lose nothing and may avoid blunders by defending where it is necessary in the long run (teire) before playing dame. The book is training you to recognise teire.

Teire before dame

You have not actually shown a passage that tries to ingrain the habit of playing teire before all dames, even though it is sensible.

A dame, by definition, gains nothing, so playing teire before dame loses you nothing, and I do not think that is ever incorrect! If playing what you think of as dame means you do not need to play teire, than it was not dame. Can we devise a situation where it is better to play dame first?

  • If you play a dame, they play a dame and you play teire, the score is the same as if you played teire, dame, dame.
    • If they play the dame you would have played first, they leave you some other dame.
    • If their move forced you to play teire, switching still gives the same score.
  • Even if they play a forcing sequence before their dame, that is evidently not forcing you to play the teire, so you can still switch the two moves and get the same score.

Another advantage to playing teire early is that if you have overlooked a ko somewhere, playing teire usually eliminates ko threats.

If you are not sure

The question whether and when to defend if you are not sure is a little trickier. If you are not sure if it will be necessary in the long run, and you do not want to lose points by playing it if it is not, you can at least wait as long as you are sure you can answer whatever your opponent does. This has some advantages:

  • It is easier to read once more moves have been played.
  • You do not need to waste time reading variations that are not played.
  • Your opponent may miss the best line, giving you a chance to defend without a loss.

You do, however, need to do the trickier reading if you want an accurate estimate of the score, and, as xela points out, you will learn more by only defending when you are sure you need to. If you reach a point where you are not sure if you need to defend immediately, then you should defend if you are comfortably ahead, but not if the game is very close.

@PJTraill Thanks for the answer!

Well, “my recommendation is that you find and play all defensive moves before actually filling the dame.” and “In general, if you’re unsure whether or not you need to defend, then I’d say don’t do it” seem like mixed opinions, right?

Maybe there’s some language issue on my side, since english is not my native language, but I got this sense of “book trying to ingrain the habit” based on the problem statement:

“Both Black and White have to make defensive moves inside their own territories before the last dame points can be played.”, a very bold statement with a sense of urgency, which looks like it’s in the path of generalization.

When I looked at these examples, I didn’t see a problem with waiting for the opponent to fill the dame (these dames are not so “neutral”, as the examples usually exhibited when people want to teach what is a dame, but function as “attack-dames”) before I make the defensive move.

So, the first example in Sensei’s is exactly the one in the example on the right. The same sense of urgency is present in the wording there : “In the example at left, a is a required te-ire for Black, since once the dame point of b is filled, White could play at a and capture the two Black stones.” (not if Black answers at a)

What I had in mind is something like: “It’s absolutely certain that a hurricane will hit 12 months from now, so I have to build a shelter. I also know that construction will take just 2 weeks, yet I start building it right now.” Sorry for the morbid example and unrealistic numbers.

A dame, by definition, gains nothing, so playing teire before dame loses you nothing

It costs you the same point (inside your territory), but it was going to happen anyway. I’m just thinking about the order of the moves.

Another advantage to playing teire early is that if you have overlooked a ko somewhere, playing teire usually eliminates ko threats.

Now that’s a tangible argument for my apprentice’s eyes!

I also would say that playing these “attack-dame” first are sente moves, but we are talking about the endgame. But as I said, I was once shown a situation where someone didn’t play a defensive move first and once the opponent filled the dame, it was too late for the person, who gained an exposed point of invasion. I guess that was one example that settled “play defensive moves before dames” as a good habit.

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Here’s an example of a pro not realising his stones were in atari during dame filling

Or for example

from Professional players making rookie mistakes

Nice examples (although I still don’t understand the simplest cases, like the ones I posted, except for pedagogical purposes. Or even the first case of the teire in sensei’s page.

One can certainly say that under the traditional etiquette of go no one would capture stones in the dame-filling stage if both players had agreed the game was over.

I was unaware of this gentleman’s rule, let alone that the players were expected to communicate and agree on anything at the end of the game.

“The players continue to play alternately until all the neutral points have been filled and all necessary defensive moves have been made.”

Now that seems reasonable.

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This might’ve been an older traditional rule and it may or may not be still in practice. Though when you look at the records of Japanese games, often they do stop recording the game record just before the dame/teire phase, so maybe subconsciously they do have a phase like that :slight_smile:

It does technically show up in the EGF tournament rules

Finite thinking time under Territory Scoring The following applies under Territory Scoring. It is not compatible with the Ing Overtime System.The alternation consists of the competitive phase followed by the neutral phase. During the competitive phase, one or both players moving next can make a play to improve the score or to fill a basic endgame ko. During the neutral phase, neither player can do so because only dame and teire, if any, are left.

If the first two successive passes occur prematurely during the competitive phase, then the clock is neutralised, each player’s time is set to exactly 1 minute, and the clock is restarted for resumed alternation.

Until two successive passes during the neutral phase, every legal play is considered sportsmanlike.

During the neutral phase, a player has to pass if his opponent has just passed. Then on neutralised time, more dame and teire may be filled quickly in continued alternation.

I mean when we play in person, sometimes you do have people passing before dame, or stopping the clock to fill dame. I think you might especially do it in a blitz game, to be fair to your opponent. I don’t think it’s very sportsmanlike to force the opponent to fill dame on the clock, or keep passing because it would be quicker.

If this is still the confusion, you can think of it as like a good habit if you want to avoid mistakes. You can think of it as a way of removing ko threats, in cases there’s the threat of a ko (it can happen from mistakes, it can show up in the dame filling, there can be a ten thousand year ko or some funny situations where a ko isn’t resolved until the very last move).

On the other hand you can just think of it like a kind of implied move order.

Ordinary endgame: where both sides could gain/lose a point. Black will probably get to play here first, but white in theory could push in once before defending.

Teire: Nobody really gains points, but white will eventually owe a move inside to fix a weakness, shape etc.

Dame: In Japanese rules, nobody gains any points, there’s no need to respond to the move even.

Typically endgame moves that can change the score will be played before teire, and teire will be fixed before the last dame.

There’s exceptions, you might force someone to fix the teire as a ko threat, you might squeeze it in if the follow-up is big enough that someone can’t make a gain by ignoring it, but you don’t lose anything typically by leaving it until much later.

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Yes, this was the confusion, your second example. Making it a good habit to avoid ko threats is indeed already a convincing argument :slightly_smiling_face: If making a move that gains points during the dame phase is considered poor sportsmanship, I wonder what a championship would be like if it were like a poker table, with a player teasing the other (although I’m not sure how far that’s still allowed) :grin:

Cultural aspect like not making your opponent lose face comes into consideration. If you push him to commit a stupid failure when obviously he should have see what happens, that can be seen as insulting, well at least in some culture.

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