Korean multi-instrumentalist Letter Flow emerged from K-pop’s indie scene in the mid ‘10s with an assured line in sincere piano ballads for grey days and broken hearts. Emotions rise as his songs swell from minimal arrangements featuring just keys and vocals, to expansive, rousing paeans to love that come layered with strings and percussion to hold aloft his remarkable voice, with its emphatic falsetto or tingling vibrato. Warmth comes from luxurious Fender Rhodes notes that nod to ‘70s soul, and his versatility shines—whether solo or in duet—on tunes with a breezier acoustic vibe.