If you are in Japan, and entering a traditional store or restaurants, you will find a curtain like fabric hung on the entrances. This curtain like fabric is called "noren" and it is usually have one or more vertical slits cut from the bottom to nearly the top of the fabric, allowing easier passage or viewing.
Noren are rectangular and come in many different materials, sizes, colors, and patterns. Then, when the noren is hung outside the entrance, it means the store or restaurant is open. Which means noren is placed upon opening and taken down when closing.
Noren was originally used to protect from wind, dust and rain. Also used to hide inside from viewers passing by.