In Japan, strands of paper string (mizuhiki) are used to decorate gifts and ceremonial utensils in much the same way ribbons are used in the West. Not only are they colorful, but a mark of elegance and respect. When you attend a wedding ceremony, you put a congratulatory gift money in these envelopes. Also, when you attend a funeral, you put it in an envelope with a blackish design and hand it to the receptionist. It will be a very important courtesy in business, so please remember it well.