Know if you’re recognized as a gaijin?

In other parts of the world, locals will speak in English when they recognize the person in front is a foreigner. This is a good way of knowing if the local easily recognized one as a foreigner. In Japan, it seems that locals will speak Japanese even after recognizing the person is a foreigner.

[1] How can you tell if the Japanese local recognizes an Asian or an Asian looking non-Asian as a foreigner?
[2] Do Japanese stare at foreigners or they also stare with their fellow Japanese?

I look super Chinese and people would ALWAYS automatically assume that I speak English after I said 'nihongo wakarimasen'.

I've never seen anyone keep speaking Japanese (or try to speak another East-Asian language) after saying that...

What an unusual question!

In Japan, it seems that locals will speak Japanese even after recognizing the person is a foreigner.

No, such a generalization is wrong. I am a visible foreigner, and a lot of Japanese speak in English to me. It depends on the place and person, but being addressed in English is definitely not uncommon in Japan for a visible foreigner.

How can you tell if the Japanese local recognizes an Asian or an Asian looking non-Asian as a foreigner?

Why are you asking? What situation do you have in mind? Generally it is not possible to tell unless you somehow interact with them, otherwise most people won't care about other people. Some people will easily recognize certain non-Japanese Asians as foreigners by their looks or suspect that they are not Japanese. Others may recognize or suspect it by your fashion, hair style or behavior, and finally, of course, by your Japanese language skills.

Do Japanese stare at foreigners or they also stare with their fellow Japanese?

Most Japanese people do not stare at anybody. It is considered bad manner. But some curious people, especially children, may stare at people that look different from other, may they be foreigners or special looking Japanese.

I don't know what Japan you've visited but its completely the opposite of the one I live in.

In the Japan I know even if a foreigner speaks perfect Japanese and is clearly speaking it and understanding it then Japanese people will often say "No English! No English!" and not talk Japanese.

I speak of extreme cases of course. But it is much more common than people just speaking Japanese regardless.
Which I don't mind really. If they don't know English then at the least they're trying to communicate the only way they know rather than just running away.

Japanese staring at people isn't anywhere near as common as you hear on internetland, though it does happen occasionally. Never with oriental people, they're super common, Asians too don't get it too much. White people....maybe blondes get it a lot but brown haired white people are rather common these days. I guess black people get it most.

It is wrong to say that in other parts of the world if someone think that another person is a foreigner they will talk to that person in English!

Not everybody speak English in Europe, for example! In very touristy places, like downtown Paris or Venice, staff in stores and restaurants may say good morning or good day or..and when you say something may answer in your language, if they know it. (tourists should actually be the first ones to say bonjour, buon Giorno etc...)

I once asked for a room in a small hotel in Venice in my very basic Italian. The owner congratulated me then asked "would you prefer to speak in English, French, German?"

In Japan I was once asked by students in their late teens if I minded speaking with them in English...after a while one asked if I spoke French. I said yes and they switched to French..they were slow but much more fluent than in English...

I guess I look a bit Japanese and Chinese, which is why Japanese people always used Japanese when talking with me. Anyway, after my slow and broken response in Japanese, they'd sometimes just say thanks and go on their way, e.g., when they ask me for directions. I have also been to some stores in Akihabara where they refuse to talk in English even though I was interested in buying things. Fortunately, there's always the foreigner staff one can bargain with.

Uhm ... Japanese WILL try to speak English with you more often than they'll try to speak Japanese with you which can be quite annoying at times.
I've been in Japan for many years now. English is not my native language. Why the hell should we communicate in a language that is not our mother tongue?
It's especially annoying if you're in a hurry and just quickly need some information and they try to use their bad English at you. That makes me really mad sometimes. Almost missed a train because of that a few times.


And yes, there WILL be staring.
I ranted about it here: http://zoomingjapan.com/life-in-japan/staring/