Mayonnaise is not a traditional Japanese food item. But since it’s introduction to Japanese society, the popularity increased rapidly, and it now has its own place in Japanese cuisine.
In Japan, mayonnaise is not only for potato salad, tuna salad, and sandwiches. It is regularly used as one of the toppings of okonomiyaki (a Japanese style savory pancake which includes vegetables, meat, and shellfish and other variety of ingredients) and takoyaki (about 1″ ball shaped grilled snack made of flour, seasonings, some vegetables and chunks of boiled octopus).
“Mayorer” is a recent made up word to describe the people who love mayonnaise so much that they add a large amount on top of almost any kind of food, such sushi, grilled fish, cooked rice, vegetables, fried noodles, soup noodles… to name a few. But just like pouring ketchup on anything in America, it’s not considered to be a good manner.
Japanese mayonnaise tastes pretty different from the American counterpart. While American mayonnaise is made to go well with sandwiches, the Japanese brands are made for Japanese food. Each brand of Japanese mayonnaise tastes different, but Kewpie has a 80% market share.
You can find Japanese mayonnaise at Japanese grocery stores. Here are some links to order online, if you can’t find it in your neighborhood;