Successful invasion under Japanese rules?

[Joelnelsonb]

Correct me if I'm wrong: under Japanese rules, you don't count live stones as points. This means that all that's necessary for a successful invasion into your opponents territory is that you don't place more stones than your opponent has to place in order to kill you. If I place ten stones in your territory and they all die, you've just gained ten points. However, if you use eleven stones to kill my group than you lost a point. Right?

[Uberdude]

Right. But I won't use 11. If I answer each of your moves it's 10 and no net change in score. If I can pass because even if you play again your invasion can't live then you lose a point. I don't need to actually play all the liberties to capture your dead stones.

[gowan]

Your argument would make sense if it were required to actually capture dead stones, but that's not the case. This SL page has some useful discussion: http://senseis.xmp.net/?Scoring%2FDiscussion

If your group of dead stones is itself threatening one of your opponent's groups, requiring your opponent to capture them to make his group alive, it is a situation called semedori in Japanese, and can be a good strategy for reducing the amount of territory your opponent makes by killing your stones see the SL page http://senseis.xmp.net/?Semedori

[Joelnelsonb]

But if you've got a large territory and I start placing stones, you've got to develop a defense right away before I get the lead to start making eyes. This by the way, is something I'm super weak at - I feel like if you have a large territory and your opponent places a lone stone somewhere, you should be able to stop him from really doing anything. Win I play, it always turns into a huge battle with the enemy usually making eyes. Are there particular patterns I'm supposed to learn for stopping specific attacks? Is this possibly what I've heard referred to as joseki?

[DrStraw]

http://www.dragongoserver.net/game.php?gid=898088

This is a game I am currently playing on DGS. Take a look at the white stone at O16 and watch how it is slowing consumed without playing against it. This should give you a clue of what people are talking about. The invasion was probably too deep, even this early in the game.

[moyoaji]

Learning how to correctly attack is one of the hardest things to do in go. However, attack and defense typically refers to middle-game strategy involving groups that have space to move around. A good rule for attacking is to never touch something you want to capture.

That status of invasions into solid territory would fall under the category of life and death. If the territory is incredibly large then perhaps it would still be considered an attack and defense problem, but usually it is just life and death. If you want to learn about how to prevent your opponent from getting eyes, I'd suggest doing life and death problems. There are many websites and books available. I use http://www.goproblems.com.

Joseki are different. They are common sequences that lead to an equal result for both sides. They usually occur in a corner. All of this information, and much, much more, can be found at Sensei's Library.

[Aidoneus]

http://www.dragongoserver.net/game.php?gid=898088

This is a game I am currently playing on DGS. Take a look at the white stone at O16 and watch how it is slowing consumed without playing against it. This should give you a clue of what people are talking about. The invasion was probably too deep, even this early in the game.

I guess there is no resign button at DGS, right?

Was this a teaching game? Maybe trying to convince your "student" that tengen is not a good early point...

[Bantari]

http://www.dragongoserver.net/game.php?gid=898088

This is a game I am currently playing on DGS. Take a look at the white stone at O16 and watch how it is slowing consumed without playing against it. This should give you a clue of what people are talking about. The invasion was probably too deep, even this early in the game.

But was it an invasion or just stones that got weak and then got surrounded?

For the OP:
In principle, you are correct. As long as your opponent has to answer each move you make inside his area, the net value is 0. And so it is under Chinese rules, so I don't think this general idea is rules-specific.

However - there are some issues you have to carefully think about:
1. Does he really need to answer each move? If not, you lose points.
2. Does he maybe answers at dame instead of inside his area? If yes, you lose points.
3. Does he play points he would have to play anyways eventually? If so, you lose points.
And so on...

And there are also some long-range considerations:
1. Does he, by answering your moves, strengthens himself (removes aji) so later he does not have to answer outside moves?
2. The issue of aji is important. Invasion, successful or not, usually fixes the shape, and this is not always desirable.
3. Do his moves strengthen him enough to start attacking you somewhere else with that strength?
4. Does your play removes ko threats you might have otherwise need?
And so on...

All those things are a (potential) loss for you. A loss which you risk just to start an invasion which gains you nothing - since as you say, even in the best case scenario - the net value will be 0. Unless you survive, of course... Which is the real issue here. If you can calculate that you survive, then play the invasion, its most often a gain for you. But if you cannot see any path to life - think very carefully and consider all kinds of other things as well.

Go is not really as simple as plonking your stones and being satisfied that he plonks his stones too.

[Bill Spight]

Go is not really as simple as plonking your stones and being satisfied that he plonks his stones too.

Hey! Works for me.

[DrStraw]

http://www.dragongoserver.net/game.php?gid=898088

This is a game I am currently playing on DGS. Take a look at the white stone at O16 and watch how it is slowing consumed without playing against it. This should give you a clue of what people are talking about. The invasion was probably too deep, even this early in the game.

I guess there is no resign button at DGS, right?

Was this a teaching game? Maybe trying to convince your "student" that tengen is not a good early point...

It is a ladder game in which he is refusing to resign. But that was not my point in posting. I was showing an example of playing inside when there is little hope.

But was it an invasion or just stones that got weak and then got surrounded?

As I said, I was showing the OP how hard it is to live inside opponents influence, never mind solid territory. As a beginner it should help him understand a little more.

[Aidoneus]

http://www.dragongoserver.net/game.php?gid=898088

This is a game I am currently playing on DGS. Take a look at the white stone at O16 and watch how it is slowing consumed without playing against it. This should give you a clue of what people are talking about. The invasion was probably too deep, even this early in the game.

I guess there is no resign button at DGS, right?

Was this a teaching game? Maybe trying to convince your "student" that tengen is not a good early point...

It is a ladder game in which he is refusing to resign. But that was not my point in posting. I was showing an example of playing inside when there is little hope.

Sorry, I did see your point, but I felt like joking. One of my character flaws, no doubt. Your game reminded me, though, of a chess tournament game some (ahem) 40 years ago in which my opponent sacrificed his last piece for my last pawn, leaving me with a knight and bishop against his bare king. If you know chess, you know this caused our game to last another 30 or so moves, thereby missing any lunch break before our next round. (This was back when 40 moves in 120 minutes was a common time control, and he used every available minute. )

[marioxcc]

Correct me if I'm wrong: under Japanese rules, you don't count live stones as points. This means that all that's necessary for a successful invasion into your opponents territory is that you don't place more stones than your opponent has to place in order to kill you. If I place ten stones in your territory and they all die, you've just gained ten points. However, if you use eleven stones to kill my group than you lost a point. Right?

Hello Joel. I'm a beginner too. I have been wondering about that too, and in my research I found that Japanese rules are not an unambiguous description of the game of Go. They are ambigous and lead to nosense if interpreted in a straightforward way. As for what I have found, Japanese rules are only an informal description of the game of Go and describe some heuristic guidelines rather than actual rules, as you might find in the much more polished Tromp-Taylor rules. See http://www.weddslist.com/j1989/index.html#8 and http://home.snafu.de/jasiek/j1989c.html.

Now, answering your question, see http://www.weddslist.com/j1989/index.html#10. Dead stones need not be captured, they're removed when playes agree than they're dead, but it's not clear what happens when the playes disagree on the alive status of stones. Note that in logic rulesets like the Tromp-Tylor and the AGA one, the life status of stones is not definied in the rules but rather it's definition and consequence is left to the players (This makes sense to me, in principle, life status needs not be defined in the rules, and the rules are axioms. It's a good practice to keep axioms as simple as possible and derive results from them). Under those rulesets, disputes over the life status of groups are solved by continuation of the game. The agreement phase (Strictly speaking there's no agreement phase on the Tromp-Taylor rules, but it's an option mentioned in the notes) is just a shortcut to arrive faster at the inevitable result of continuing the game; this is not true under the Japanese rules, because, as you noted, demonstrating that a group is dead by capturing it costs points under territory scoring. Note that the definition of dead stones under the Japanese ruleset appeals to a notion of “enabling”, whose definition/realization isn't addressed.

The Japanese ruleset also contains ambigous provisions which may call for the game to end in “no result” and “both players lose”.

I see no reason for mankind to continue using Japanse rules. Please note that agreement phase is ideally a shortcut to arrive faster at the result of applying the dispute resolution means (Whether continue normal play, as in AGA rules, or use a different procedure); so if the means for dispute resolution isn't specified then there's strictly speaking no basis on which players may decide on the life status of groups; this is the case under the Japanese ruleset. Territory scoring allows players to capture the groups claimed to be dead, in the case of dispute. The Japanese ruleset requires either the players of the referee to be able to tell the life status of stones in any board position where the game ends, and the players may in principle chose to end the game at any point, so that puts upon someone the requirement to be able to solve arbitrary life and death problems (Strictly speaking, only those problems that can be reached by actual play under Japanese rules).

In practice, however, when a game is specified as being played under the Japanese rules conflicts rarely arise. Players are able to tell whether stones are alive or dead (According to a non-formally-defined common wisdom of life and death) at the end of the game, and they behave honestly in the agreement phase, disputes are rare. The case concerning your question is not likely to happen, as the player claiming that his lone stone in enemy territory is alive has nothing to gain. The referee (If a formal match) would refuse to accept his claim, and in informal matches, the other player would simply react the same as if his opponent did an illegal move and refused to take it back. Note that this result, in both cases, isn't based upon the rules, because they don't specify clearly what to do when this happens, but based on common sense and wisdom instead.

It's claimed sometimes that Japanese rules are sharper, because under territory the addition of black stones and territory, white stones and territory and seki points sum to the total board points (361 for size 19). If there are no points in seki, this means that the score difference (before adding komi) is odd, and so it varies in increments of 2, rather than increments of 1. I don't see this as something undesirable, but at any rate, Button Go (Awarding 0.5 extra point to the first one to pass) re-introduces this kind of “sharpness”; note that the actual value difference of passing first to passing second is 1 point (You get 0.5 extra points, and your opponent doesn't).

Regards.