A nod between two foreigners (jp. gaikokujin, short: gaijin), who randomly pass each other on the street in Japan. Although they don't know each other, their common feeling of being an alien in Japan triggers the mutual need of performing the nod with the subcontext "You are not alone!" or "Yes, I think everything is strange here, too."
While commonly performed by foreigners who just arrived in Japan or who havn't been there for a long time, foreigners who have stayed in the country for a longer amount of time and have already immersed into the culture, might feel offended or annoyed by receiving the nod. Their stiff reaction on the other hand might be understood as "Dude, I have been here for some time now. Nothing is really special to me anymore." or "Please, don't embarrass me and yourself."
While the gaijin nod has become rare in urban areas with lots of foreigners, it is more likely to be observed and experienced in rural areas or suburbs.
Various discussions evolved around the question, whether it is appropriate to perform the gaijin nod or not. While some mark it as unnecessary and unnatural, others are convinced that it certainly does not hurt to share a smile on the street.
Gaijin 1: I experience a strong sense of comradeship, whenever I receive the gaijin nod on the street.
Gaijin 2: Everytime I receive the gaijin nod, it feels like I don't belong here.