It is expressed in the change of plucking method: sanxian was plucked with giso (a pick shaped like a nail), but shamisen was plucked with bachi for 'Heikyoku' (the music played on Heike biwa as accompaniment for the recitation of Heike monogatari) which they specialized in.
三弦が義爪を使って弾奏していたのを改め、三味線の弾奏に彼らが専門としていた「平曲（平家琵琶）」の撥を援用したのもそのあらわれである。