crushed garlic. Soup recipes and methods of preparation tend to be closely guarded secrets. Most ramen restaurants offer a system known as (), where customers who have finished their noodles can request a "refill" (for a few hundred yen more) to be put into their remaining soup. Regional variations While standard versions of ramen are available throughout Japan since the Taishō period, the last few decades have shown a proliferation of regional variations, commonly referred to as ramen (). Some of these which have gone on to national prominence are: Sapporo, the capital of Hokkaido, is especially famous for its ramen. Most people in Japan associate Sapporo with its rich ramen, which was invented there and which is ideal for Hokkaido's harsh, snowy winters. Sapporo ramen is typically topped with sweetcorn, butter, bean sprouts, finely chopped pork, and garlic, and sometimes local seafood such as scallop, squid, and crab. Hakodate, another city of Hokkaido, is famous for its salt-flavored ramen, while Asahikawa in the north of the island offers a soy sauce-flavored variation. In Muroran, many ramen restaurants offer Muroran curry ramen. Kitakata ramen is known for its rather thick, flat, curly noodles served in a pork-and-niboshi broth. The area within the former city limits has the highest per-capita number of ramen establishments. Ramen has such prominence in the region that locally, the word usually refers to ramen, and not to actual soba which is referred to as ('Japanese soba'). Tokyo-style ramen consists of slightly thin, curly noodles served in a soy-flavored chicken broth. The Tokyo-style broth typically has a touch of dashi, as old ramen establishments in Tokyo often originate from soba eateries. Standard toppings are chopped scallion, menma, sliced pork, kamaboko, egg, nori, and spinach. Ikebukuro, Ogikubo and Ebisu are three areas in Tokyo known for their ramen. Yokohama ramen specialty is called Ie-kei (). It consists of thick, straight noodles served in a soy flavored pork broth similar to , sometimes referred to as, . The standard toppings are roasted pork (chāshū), boiled spinach, sheets of nori, often with shredded Welsh onion () and a soft- or hard-boiled egg. It is traditional for customers to customize the softness of the noodles, the richness of the broth and the amount of oil they want. Wakayama ramen in the Kansai region has a broth made from soy sauce and pork bones. Hakata ramen originates from Hakata district of Fukuoka