Harusame ("spring rain") noodles aren't really noodles.
They are commonly called "glass" or "cellophane" noodles in English but they aren't really glass or cellophane.
They are made from the starch of green mung beans.
They are usually sold dried and must be soaked briefly in hot water before using in most dishes unless you are using them in a soup. They can also be deep-fried.
Although some people dislike their texture, the thin translucent appearance of these noodles is cool and refreshing, like a spring rain.