The inspiration people seek: “See Naples (Napoli) and die,” meaning that before you die, you have to experience the beauty of Italy’s city of Naples, is an expression known in Japan as well. There is a special, even magical allure evoked by the name “Italy” in the minds and imaginations of many Japanese. It’s a place where the traveler will find ancient ruins and artifacts from the Roman Empire, Renaissance art and culture, the beautiful landscapes along the coasts of the Mediterranean and the Adriatic, the magnificent Alps that rise at the country’s northern borders, and the myriad and beautiful products of Italian craftspeople. The opening expression (Vedi Napoli e poi muori in Italian) was eventually translated into Japanese, and if you ask people in Japan about their destinations of choice, many will say Naples. This too is a part of the Japanese image of Italy. Read more However, the fondness of many Japanese for napolitan spaghetti and the images it brings to mind are entirely Japanese. As you can see from the photo, it’s not a traditional Japanese dish, but today it has unmistakably become a dish representing Japanese soul food. The associations it has in the hearts and memories of the people are even deeper and more numerous than those of another Japanese favorite, gyudon (bowl of simmered beef strips and onions on a bed of rice).
No matter what our fast-changing times may bring, the personal associations and memories the word napolitan brings to mind will only continue to grow among the Japanese. The number of Japanese people who don’t even recognize the reference in its first three syllables to the Italian port city will also surely grow with each generation. Napolitan is one more excellent example of Japan’s assimilation, and eventual Japanization of things foreign.

In short: The origin of the Japanese word napolitan is of course the Italian port city of Naples (Napoli), famous around the world for its scenic beauty and acknowledged by its status as a UNESCO World Heritage site. It also comes from the word “Neapolitan” in English, meaning a person from Naples. Regardless of these original meanings, napolitan holds a unique place in Japanese culinary culture today, and you will find it very hard to find somebody in the country, regardless of age, who hasn’t eaten this truly “national dish.” Read more Although the basic ingredients are a sauce mainly using American-style ketchup, and long, thin round cross-section pasta,^* napolitan is a dish that will greatly vary by region, restaurant and home. Some examples are variations in the thickness of the pasta (spaghetti), how long it’s boiled, the toppings (sausages, green peppers, onions, etc.), how those toppings are stir-fried and whether it’s served up and decorated on a normal plate or a preheated iron plate.
Based on its name, the dish that should be the origin of napolitan is Spaghetti alla Napoletana that’s eaten in Italy as well as neighboring Switzerland, France and Germany, but the only thing the Japanese version has in common with its namesake is that it uses spaghetti.
Italians that visit Japan are unanimously perplexed and surprised to find that this dish using one of their country’s staple foods, not to mention borrowing the name Napoli, has undergone its own unique development in the Far East to now occupy an irreplaceable place on the Japanese table.
*In Japan, napolitan is generally called “spaghetti,” but the Japan Agricultural Standards designate “spaghetti” as solid noodles 1.2 mm or more in thickness, or hollow noodles up to 2.5 mm in thickness.

Some background: Napolitan is thoroughly a part of the popular Japanese menu, but surprisingly little is known about its origins. The only thing we can say with some certainty is that the dish’s history in Japan began some time after the Meiji Restoration (1868)—a series of events that can rightfully be called a revolution—in which the world of the samurai was swept away and virtually all aspects of Japanese society, including the food eaten, the values held and the way people thought, underwent dramatic changes. Read more As with the other standard “foreign dishes” that arrived and were assimilated into the Japanese daily menu, like karei-raisu (curry and rice), hayashi-raisu (hashed beef/beef stroganoff and rice), omu-raisu (omelet and rice), bifuteki (beef steak), and tonkatsu (deep-fried pork cutlet), there are numerous theories about how napolitan came to be what it is. Wikipedia (in Japanese) alone offers five theories about the origins of napolitan in Japan, and you will find several referenced articles on the subject. Recently, the customs department of Yokohama has contributed to the “debate” surrounding napolitan, but there is still no universally accepted story (and so the quest for the answer continues).
Over the last 50 years, consumption of napolitan has spread to all corners of the food services, from the menus at family restaurants, cafeterias and kissaten to the boxed lunches sold at supermarkets and convenience stores, as well as the home dinner table and school lunches. This profusion and popularity ensures the evolution of napolitan (and bellies full of it) will continue.

Thanks to Sabouru (Coffee shop Sabor)