There are some dishes in Japanese which do not exist in the original country. Good example is Napolitan which is a spaghetti based dish but it does not exist in Italy. The name Napolitan comes from the Italian city, Naples(Napoli).
Napolitan is a spaghetti with ketchup, sausage/ham/bacon, onion and green pepper. The spaghetti is boiled as same as other spaghetti dish but then cooled. In restaurants, chef boils the substantial amount of spaghetti in advance and keep it in the fridge. When the kitchen gets the order from the customer, the chef pan fries the spaghetti with other ingredients. The spaghetti is cooled to avoid the time for boiling the spaghetti per each order.
Actually Napolitan is a dish offered at coffee shops or other small diners where there is just one chef. Then, it is interesting that it is not offered at Italian restaurants in Japan. Therefore Japanese do not think that Napolitan is an Italian cuisine.