:: Igo Hatsuyôron 120 (2015)

About Ko in a Semeai Between

Two One-Eyed Groups (2012)

(Referenced by 190; 227; 818; 937)


This chapter explains the theoretical foundations of a special type of semeai, which arises in Joachim Meinhardt's idea ( 219) to prevent White's large endgame in the upper left corner.

The presentation follows the course of our growing insights into this particular formation. For a long period of time we were unsure about the best time to start the ko-fight, especially whether White should choose an "early" ko (i.e. a few moves after creating the ko-formation) or a "late" one (i.e. after Black connected the hanezeki's tail).

Please understand this chapter to be supplementary only now; probably it might be still useful for readers with a more mathematical approach.

It was written before our intense work on "Putting the Cart Before the Horse" ( 937) - using the method of reverse engineering, instead - which shows our up-to-date results. We ask for your kind understanding that we still shied the effort synchronising both chapters. However, it has always been found to be advantageous to illuminate a situation from several directions. Mismatches were always quite helpful suggestions for further intensive studies.

A Special Type of Semeai 1134
The Simple Version - No Hanezeki 1135
      Larger Eyes 1140
      A Second Ko-Shape for White 1141
            [ Second Ko-Shape for White & Larger Eye for Black ] 1142
      A Second, and Shared, Ko-Shape 1144
            [ Shared Ko-Shape & Outside Ko for White ] 1146
The Effect of the Hanezeki 1148
      Effective liberties 1149
      Number of Ko-threats 1151
      White's False Eyes 1152
            [ Larger Eye for Black ] 1153
            [ Shared Ko-Shape in the Centre ] 1157
      The Semeai with Black's Group in the Lower Right 1160
            [ Black's Effective Liberties ] 1161
            [ Impact on the Main Ko-Semeai ] 1162
            [ The Construction Process Makes the Difference ] 1164
White's Group on the Left Edge 1166
Conclusion 1167

Copyright © 2016 Thomas Redecker.

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