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RobertJasiek/Efficiency

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Table of contents Table of diagrams
fewest number of plays
greater number of plays
efficient
inefficient
territory efficiency 0.67
territory efficiency 1
territory efficiency 1.83
inefficient: too slow movement
efficient: good compromise between speed and safety
inefficient: too insecure

Number of plays

A player's greater efficiency achieves a) something with the fewest number of his plays or b) the most with the same number of his plays.[1]

Note that plays made for then removed stones are also counted.

Example 1 for different numbers of black plays resulting in different, compared positions: Suppose the task is to create a solid black wall in front of the white stones.

[Diagram]
fewest number of plays  

Black achieves the task with 6 plays. This is efficient.


[Diagram]
greater number of plays  

Black achieves the task with 7 plays. This is inefficient, because Black spends one play too many, which he would better play elsewhere.


Example 2 for same number of black plays: Suppose the task is to live while making the most territory. Each diagram needs 6 black stones played.

[Diagram]
efficient  

Black has played 6 stones to get life with 4 points. This is efficient.


[Diagram]
inefficient  

Black has played 6 stones to get life with at most 3 points. This is inefficient.


Territory efficiency

The territory efficiency of a player's territory region is his current territory there divided by his number of stones played to achieve it.[2]

Example 3

[Diagram]
territory efficiency 0.67  

Black has 4 points made by 6 stones played. His territory efficiency is 4/6 ~= 0.67. This is inefficient.


Example 4

[Diagram]
territory efficiency 1  

Black has 6 points made by 6 stones played. His territory efficiency is 6/6 = 1. This is better than in Example 3. In relation, Black has made territory more efficiently.


Example 5

[Diagram]
territory efficiency 1.83  

Black has 11 points made by 6 stones played. His territory efficiency is 11/6 ~= 1.83. This is more efficient than in Examples 3 and 4.


Movement speed

Efficiency is the optimal compromise between safety and speed of local movement.[2]

This more specialised description of efficiency has, however, its merits for related application.

Example 6

[Diagram]
inefficient: too slow movement  


[Diagram]
efficient: good compromise between speed and safety  


[Diagram]
inefficient: too insecure  



Footnotes

[1] Citation from and invented in a draft of a book of Robert Jasiek.

[2] Citation from and invented in Joseki Volume 2 Strategy.


RobertJasiek/Efficiency last edited by RobertJasiek on March 24, 2013 - 15:47
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