It may be thick, thin, or even ribbon-like, as well as straight or wrinkled. Traditionally, ramen noodles were made by hand, but with growing popularity many ramen restaurants prefer to use noodle-making machines to meet the increased demand and improve quality. Automatic ramen-making machines imitating manual production methods have been available since the mid-20th century produced by such Japanese manufacturers as Yamato MFG. and others. Soup Ramen soup is generally made from stock based on chicken or pork, combined with a variety of ingredients such as pork bones, katsuobushi (skipjack tuna flakes), niboshi (dried baby sardines), beef bones, shiitake, onions, and kombu (kelp). Some modern ramen broths can also be vegetable-based. Tare is often added to broth to make the soup. (, 'pork bone'; not to be confused with tonkatsu) soup is broth with a typically translucent white colored appearance. Similar to the Chinese baitang (), it has a thick broth made from boiling pork bones, fat, and collagen over high heat for many hours, which suffuses the broth with a hearty pork flavor and a creamy consistency that rivals milk, melted butter or gravy (depending on the shop). Although is merely a kind of broth, some people consider tonkotsu ramen (specialty of Kyushu, its birthplace) a distinct flavor category. (, 'chicken bone') soup based on chicken bone broth originated mainly in Tokyo. It is often used as a base for salt and ramen. Flavors The resulting combination is generally divided into several categories. Although newer and older variations often make this categorization less clear-cut, a description of said old variations is as follows: (, 'salt') ramen is the oldest of the four types. It has a pale, clear, yellowish broth made with plenty of salt and any combination of chicken, vegetables, fish, and seaweed. Occasionally pork bones are also used, but they are not boiled as long as they are for ramen, so the soup remains light and clear. Chāshū is sometimes swapped for lean chicken meatballs, and pickled plums and kamaboko (a slice of processed fish roll sometimes served as a frilly white circle with a pink or red spiral called narutomaki) are popular toppings as well. Noodle texture and thickness varies among ramen, but they are usually straight rather than curly. Hakodate ramen is a well-known version of ramen in Japan. (, 'soy sauce') ramen has a clear brown broth, based on a chicken and vegetable (or