Ha. Can confirm. Lived there 2 years and while I love the food, as far as I can tell there is no food available anywhere in Japan, at all, that the average south east asian would recognise as even mildly spicy. And outside the home islands I have observed Japanese people reacting hilariously to the actually spicy local food. My favourite was a co-worker who literally collapsed to the floor in the foetal position moaning after eating a mala hotpot which was, at best, medium heat.
Love the people, love the country, but Golden Curry's bright warning red "EXTRA HOT" is not bloody hot at all.
All of that being said, mild is definitely what to expect unless you ask for spicy or go out of your way for a specific dish.
But also at a wagamamas in London I had them do double extra hot on their hottest dish and could barely tell. I'm American from the Midwest living in Seattle.
I refer to many spicy thing like that golden extra spicy as "spicy as katsup"
But it can be hard to communicate to some people when their upper level of spice tolerance is banana peppers.
It might just be a thing around here, but a lot of Indian or Thai restaurants have two separate heat scales, the 'normal' one, and the Indian or Thai one. One of the Thai restaurants that I used to frequent, for example, had a scale where 'spicy' was the same as 'Thai mild' and 'Thai spicy' would genuinely make your hair stand on end.
I'll have to try and find the Kotlin extra hot at the Eastern European grocery by my house.
Fair warning: "Kotlin Extra Hot", although a bit spicy, still doesn't hold a candle to what Indian cuisine can offer (or Japanese — e.g. wasabi).
I chuckled at the basis of your comparison being a globally commercialized instant product.
I usually do a 5 to 8 on Japanese scale, though 3 or 4 is fine when eating with more sensitive people. 1 is tooo sweet, even when I was in grammar school, although it's marketed in Japan towards kids. If an Indian restaurant in USA offers only "mild, medium, spicy", I should choose mild because medium will cause about 30 hours of pain along the entirety of my digestive tract.
Erm, if you've had a proper curry recently then you probably will be. Like everywhere else, foreign foods get tailored to their locality or they die. If you fancy a naan filled with sugar and some pretty bland dishes then try an "Indian" restaurant in Japan. Which should come as no surprise, because plenty of other so-called spicy foods here are a) not spicy, and b) surprisingly/sadly, overly sweet.
That's not to say that you can't get a decent curry here, but you'll have to try harder than just walking into a random curry house. And this…
> Indian restaurants outnumber the top 3 pizza chains of the country put together!
I think the only food more maligned by localisation in Japan than pizza could be Mexican food, which leads us back to spice and sugar. I'm not sure what having more curry houses than pizza huts in Japan proves. It would mean something in the US or Italy, but in Japan?
Tastes differ.