An instrument only seen twice in the whole Naruto anime. While being a simple muscial instrument, both characters have shown vital knowledege and skill in using it.
Using this flute, Tayuya can cast genjutsu and control her Doki by playing specific melodies. This is the only item she keeps with her. She says that no one that has heard the sound of her flute has lived. If the opponent recognizes her melody she can change it to confuse them. The flute was cut in half during her battle with Temari.
Given to him by Itachi as a redemption preasent, this odd insturment has been passed down the Uchiha family line for generations. Sasuke is one of few Otogakure shinobi to actualy use sound as a fighting style. Dispite recently acheiving this, he was shown to have have immense skill using it. In his first fight with Tigerstar, he was able to dodge attacks and play the flute simultaneously. The flute boost Sasuke's genjustu by 30% and allows him to use special ninjustu and Genjustu that can not be casted by normal means. It is also a great insturment for down time, it's music is said to be legendary. It was this reason why Sasuke was one of the shinobi to be picked as Otokage.