There is a noodle called Hiyashi chuka in Japan. If you translate into English, it will be cooled Chinese. Therefore everyone thinks that this dish is a Chinese dish but actually it does not exist in China. This is one of the Japanese cuisines that Japan has adapted from abroad.
It is a cold noodle using ramen noodle but there is no soup but just sauce. Then, the toppings or accompanied ingredients are different from ramen. For example, tomato, cucumber, sliced ham and sliced omelette are never used for ramen.
Hiyashi chuka has two different sauces. The first type is soy sauce based sauce with rice vinegar. Then, second type is sesame creamy sauce. Then, due to it is cold noodle, most of the restaurants or diners do not offer Hiyashi chuka all year around but just during summer. Restaurants and diners which offer Hiyashi chuka as seasonal menu usually put the sign on their walls or doors to attract the customers.
Cold noodle offered just in summer sounds not strange but other cold noodles, cold udon and cold soba noodles are offered through the year. Therefore it is quite unique that you cannot eat Hiyashi chuka in winter.