Kammala wannan jumla: Miyahara ya cancanci shiga gasar matasa ta kasa da kasa a kakar 2011 <unk> 2012. Ta lashe lambar azurfa a gasar farko ta Junior Grand Prix a Gdańsk, Poland, kuma ta kammala ta biyar a gasar ta biyu a Milan, Italiya. Miyahara sa'an nan ya lashe
Gasar matasa ta Japan kuma ta kasance ta shida a matakin manya. Ta kasance ta huɗu a Gasar Zakarun Duniya ta farko. An gayyaci Miyahara don yin wasan motsa jiki a cikin bikin a gasar cin kofin duniya ta 2012 a matsayin zakaran zakarun kasar Japan.