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?
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?
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?
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.
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.
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.
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.
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.
Now, I’m getting mixed opinions 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 …