Shio ("salt") ramen is probably the oldest of the four and is 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 tonkotsu 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 shio ramen, but they are usually straight rather than curly.