Shirataki is noodle-shaped konnyaku
mostly served as "gu (item)" for sukiyaki
. This name derives from the word "white cascade". Although it is almost tasteless itself, it absorbs broth well. Since more than 95%of it is made from non-calorie konnyaku
starch rich in fiber, it is regarded as a healthy diet food.
Technically, shirataki is not categorized into noodle. Noodle is made mostly of such grain as wheat, soba and rice, but konnyaku powder is not considered grain.
Most Japanese can't tell the difference between shirataki and ito-konnyaku because of its similarity. Although both ingredients are just the same, shirataki is made from konnyaku gel pushed through perforated cylindrical container and consumed mainly in the Kanto Region, whereas ito-konnyaku is first made into a block of konnyaku and then shredded into thin pieces, and is popular in the Kansai Region.
A tip for cooking sukiyaki: Shirataki should be boiled for a short time separately from other "gu" beforehand because of brownish scums coming up when stewed. Also you should cook it away from meat because calcium hydroxide in it hardens protein of meats and makes them blackish, which is a huge minus for Japanese food culture that is highly particular about colors of dish.