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to play (a stringed or keyboard instrument)
「弾く」 has another reading with different meanings.
to flip; to snap; to flick
毎晩まいばんピアノを弾いひいている。
I play the piano every night.
姉あねがギターを弾くひくのが上手じょうずだ。
My older sister is good at playing guitar.
子供こどもの頃ころからバイオリンを弾いひいていた。
I've been playing violin since childhood.