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Question About Japanese Scoring
  Difficulty: Beginner   Keywords: Question, Rules

[Diagram]
Diag.: Scoring Issues (Japanese vs. Chinese)

In this example, white has 16 empty points surrounded, which makes for 16 points under the japanese system. My question is this: In most games I have played, a formation like this would be left alone, yet as I see it, since you lose points if you play within your own area, would it not do black good to play:


[Diagram]
Diag.: Scoring Issues II

Now, white only has 12 surrounded spaces! Yes, black lost one stone, but white lost 4 points! It seems counter-intuitive to me why this would normally be left alone until the end of the game. (When I have scored games using ViZiGo, the score is exactly the same in both cases... which doesn't make sense to me.)



BillSpight: Hmmm. My guess is that ViZiGo actually computes the area score? and converts to the Japanese score (territory?). With area scoring you do not lose points by playing inside your own territory, because the area remains the same. Area scoring is a easier to program, I believe.

By territory scoring White has lost 4 points of territory, but gained 1 captured stone, for a net loss of 3 points.


[Diagram]
Diag.: Scoring Issues (Japanese vs. Chinese)

The key point to remember that you can remove dead stones at the end of the game for free! So, if black plays 1, white should play 2, as it fences black in and doesn't decrease the territory. You had 16 points of territory. Now we have 15 because of 2, but we get a prisoner, because we get to remove 1 at the end of the game. So we have the same score.



Bill: As HolIgor points out below, W 2 is not necessary.


[Diagram]
Diag.: Scoring Issues (Japanese vs. Chinese)

If black plays 3, white can respond at 5 without altering his score. If black continues to play stones in white's territory, white can answer them without altering the score. White can even gain points by ignoring black moves. 7, for example doesn't need to be answered. The black group is unconditionally dead. After removing the black stones at the end of the game, white will have 3 less points of territory, but will have 4 prisoners!


[Diagram]
Diag.: Don't waste arrows on a corpse

White should not respond to 3 with 4. The marked stone is dead until proven otherwise. If black adds more stones inside white's territory, THEN she should respond with stones of her own inside her territory.

-- FCS



[Diagram]
Diag.: Don't waste arrows on a corpse

Let me add several words to the last diagram. White should not reply at all in this situation, black stone will remain dead anyway and thus white would increase the score by 1 point. Imagine how many moves black should make to live in the corner. This is an example. Only after 4 black moves white makes a move that secures a kill. Other moves may be used to take some profit elsewhere.

It is interesting to note also that even if white ignores 8 in the diagram black will have live and will take 16 points from white spending 5 moves for it. This makes about 3 points per move which is pretty low in the middle of the game.

 --HolIgor


Bill: Black should live at a, not 8. If B 8, W a - B b, W c makes ko, threatening to kill Black's group by removing its second eye.

If Black lives he takes away 14 points and makes 3 for a swing of 17 points.




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