Video 1: Instructor playing the 二胡 (ㄦˋㄏㄨˊ) "er4 hu2":
"Erhu"
Video 2: Instructor playing the erhu
A closer look at the parts of the erhu:
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(Image taken from this site)
Video 3: Instructor playing the 籥 (yue), which was described earlier in the follow-up report to the Confucious celebration: