How to tie the “Fly-heads”
All seven strings have a “fly-head” (ying-t’ou, 蠅頭). They go through the “yarn fasteners” (絨扣) to secure the string, and thus (the strings) cannot slip out. Take the head of the string and twist it into three parts (total). (On the left) make two parts (of the three) with the string head in the center and (overall) facing up (Of the left hand two parts), the first bend should be below and twisted to the right. The second part should be above and bent to the left. The string head remains in the center, and is face up. Using the left hand, thumb and index fingers, pinch (the left-hand portion), and with the right hand put the (right) circular part out over it (the left-hand part), slipping it over the center of the (left-hand) two folds and drawing it tight. Tie it up like a fly’s head. On the left, and right, it should seem to have two eyes. The top center should be like a straight nose. The back ply should have the form seen in the bottom picture. Put it through the yarn fastener, tighten, and arrange it in a straight manner, on top of the (ch’in) bridge. Make sure the round circular hole is pulled tight to the limit, thus perfecting the form. Ideally the result should be neat and small.. Hopefully the pictures will aid the understanding.
Figure 1: Picture 1 (the first picture at the top, going from top to bottom) shows the starting position for making the “fly-head”, with the string folded into three parts. Picture 2 shows how to fold the right hand circular part over the left-hand part to construct the nearly completed knot. The bottom two pictures show the nearly finished knot from the top view, and from the bottom view. Each of the bottom two pictures has a smaller, tighter cousin on the side.
 “Ying-tou”, or “fly-head” is a term for the little bow-tie knot found at the end of the ch’in string that is run through the “yarn fasteners” and placed on the top of the Yueh-shan bridge. Presumably this is called a “fly-head” because the two bows look something like the large eyes of a fly. Of course, the bows are important, because otherwise how would the ch’in string be held at the bridge end?
 See Figure. At this stage, we more or less have the topmost picture in Figure 1.
 According to Figure 1, this gives us the picture, second from the top.
 See Figure 1, the bottom and last “back” picture of the four.