I think you overstate things . For one , in S 1 E 1 Kumiko doesn ' t seem to be thinking about following her sister ' s example except in a trivial , incidental way . Her fresh start consisted of picking a high school , not for its academic reputation , but for its uniform . Kumiko ' s impulsive decision not to join the band comes in answer not to a question from Mamiko but to a question from Shuichi . And Mamiko ' s question doesn ' t reinforce Kumiko ' s first decision but instead sends her into a reverie that ends with her changing her mind . I don ' t see Kumiko following Mamiko in any of this . I also can ' t accept that in the early episodes of season 1 Kumiko is motivated to be in the band and play the euphonium . From the above her decision to join the band is haphazard , and even after she decides to join , she wants to change her instrument . It ' s only by chance Aoi ' s comment in front of Asuka that she ends up continuing to play the euphonium . We don ' t see Kumiko become passionate about the euphonium until S 1 E 12 . I agree the young Kumiko was hurt when Mamiko quit band Mamiko was Kumiko ' s role model , and the role model became a disappointment . One could put it in terms of the show Kumiko was playing for Mamiko , and Mamiko abandoned her . It ' s likely the residue of that disappointment contributes to Kumiko ' s surly attitude toward Mamiko , and to her current anger . But I don ' t think Kumiko is in some psychological war of identity with Mamiko . I suspect something more mundane that Kumiko senses Mamiko isn ' t being open and honest . Mamiko is being entirely too secretive about why she made this sudden decision , and her assertion that whatever is motivating her cannot wait a year for her to finish college is suspicious . I suspect there ' s another shoe to drop . From a thematic perspective , I want to think that Mamiko is like Kumiko in the early episodes of season 1 she wants a fresh start and is going about it fecklessly .