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In J. Davies' example of the placement tesuji he gives Black trading f15 for g16 before playing b18. If White sacrifices the g17 stone and plays c16 instead he wins the corner. Am I correct in assuming this is only a good result for Black because J. Davies' example includes a Black stone at M17? A possible continuation would be Black f15 c16 b17 b18 c15 b16 b15 a17 g16 and Black has a weak group to attack in addition to her influence.
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