Meeting siblings in Japanese culture

Hi,

I'm American and I'm dating a Japanese guy. He recently told me his brother was coming to visit and asked if I wanted to hang out with him to which I responded, ''Sure'' because I didn't think it was that big a deal. He seemed to be a little nervous about the idea though and asked me if I thought it was weird at all, which I was kinda surprised by. From my point of view, meeting siblings is not the same as meeting parents and is far less significant. However, I got the impression that it wasn't the same in Japanese culture and so I would like to find out. He also mentioned that he's never done it before. Any feedback on the issue is greatly appreciated!

This is my Opinion. I do not know whether it is common or not. But I was born in country side. I know Japanese old opinion and behavior. My English is not good, but I will write.

Sometimes brothers, sisters, or relatives are treated equally to parents as a family.
Especially in the case that no one of family do not meet partner before and family are living far place.

In the case, parent cannot leave from their city because of their job, physical problem, or feeling difficulty to meet, they will send young generation or relatives to check partner.

I think his brother was deputation of the family. His family may be very confused because you are foreigner. His parents do not know how to communicate with you and feeling difficulty to accept. So, they send their son to check you.

Not sure about every family, but my experience is that my wife & her siblings did not introduce any of their boyfriends/girlfriends to their siblings before they were to be engaged. I met my mother-in-law a year before we were engaged but it was when she came to visit America. I think my wife was getting "preliminary" approval from Okasan.

how old are you?

I recently stayed with my boyfriends family in japan when we visited. There I ofcourse met his siblings, and they treated me as just one of the family. However we are only in our 20's (students) so perhaps thats why his family was a bit more liberal, even though he has told me that they were 'traditional.' In fact his brother (18yrs) used me staying there as an excuse to be able to invite his gf (japanese) over for christmas dinner, which wouldnt have normally been done, and I was apparently only allowed becuase I was a foreigner.

If i was already living in japan, I'm not sure if i would have met them or not, since we had only been dating for 1.5 years and were not engaged or anything like that. The only reason I met them at all and stayed was because I was visiting with him, and being a student, there was no way I could afford a hotel for the whole month and a half. My bf seemed pretty close to his brother though, and since we are all pretty young, I dont think he would have cared much if i met his brother before his parents.

Are you fairly serious with your relationship? thinking about getting engaged? If so then his brother could be simply 'visiting' on behalf of your parents to suss you out. Other than that, your boyfriend could have been acting weird because he is not used to his brother hanging out with him and his friends, let alone someone so personal as a gf...