Fǎn dǎ yuán 反打圆 (trad. 反打圓)

Dǎ yuán starting with the middle finger.Alternate plucking two strings one octave apart with the thumb and middle finger with closing motions. Pluck with the thumb first on the higher-pitched string, then pluck with the middle finger on the lower-pitched string. The pattern is typically played as 16th notes.