Tutorial on how to replace a han-eri on your nagajuban:
First, remove the old one using a stich ripper.
Then iron out any creases on the new one
Next, you'll have to iron creases into the new han-eri. The first creases are on the ends of it, folding in about 2-4cm, ironing and basting this.
Next, fold it in half along the long axis/(hotdog style i guess)/(fold the rectangle into an even longer rectangle), and iron this with a nice crease. This fold is oriented so that the basted side is contained inside the fold.
Next, we will do two more folds along that same axis. But the edges of the fold will have just enough space for the eri-shin to fit inside of the fold. For most plastic eri shin this will be about 5cm. Iron this down on both top and bottom sides, with the folds facing into the first long crease.
It should look like this now:
Now it is time to actually sew!
Find the middle of the han-eri and pin this over the middle of the nagajuban collar. Add as many pins as you like, being careful to get the top and bottom of the han-eri lined up nicely along all edges.
Then sew it down by hand, using an invisible stitch. The outside seam is supposed to be stitched down before the inside of the han-eri. (This is maybe because the first side to be sewn will have an ever-so-slight curve to it?)
That's it! once you're done sewing, that's all. Be sure not to sew the ends closed so that you can get the eri-shin in and out of the han-eri.
Let me know if you have any questions!



















