While shopping at the local butcher shop, I had an interesting, though not uncommon experience. When I entered the shop, an older woman, probably around 60 or so, was already there being waited on by one of the always friendly and helpful young women who works there. She had about half a pound of bacon on the scale for her and the woman was asking her questions and telling her what she wanted.
Another of this shop's seemingly endless supply of energetic and positive-thinking young women came out to help me. I asked her for my ground chicken and she promptly weighed it out for me and bagged it up. The older lady was about three feet from the cash register and hadn't moved from the time I'd arrived at the shop (I saw her through the glass doors) until the point at which I approached the register. As I went to pay, she sidled over another foot as if she wanted to make sure she checked out before me even though she was nowhere near finished making her order. Her bacon was still on the scale, unwrapped.
The moment I paid, she latched on to the young woman that had just rung me up and made her get together another part of her order for her while the first one was still helping her. I guess that she must be catering a big dinner party or something to require two people to wait on her at once. ;-)
I've seen this sort of territorial body language many times since coming to Tokyo. Growing up in a small town in Pennsylvania, I rarely, if ever saw this sort of aggressiveness. People in small towns, who are more likely to see each other again or to know one another or know someone who knows the other person, are far more likely to wave someone in front of them or back off for someone who appears to be there first. In Tokyo, I see people inching in, cutting off, jumping in front of, and out and out butting in on others all the time. I can be checking out with 6 people behind me and someone will run up to the cashier and interrupt the transaction to ask a question or insist on being served.
I see this sort of thing in tiny ways in addition to these more overt ways. For instance, if you stand at a crosswalk which isn't very crowded with people, and you are the person standing closest to the street or curb, men who walk up and wait at the crosswalk with you will make sure they stand further ahead than you so that they can get out ahead as soon as the light changes. If you inch forward so that you are equal or ahead of them, they will move ahead again. I once asked a friend to test this and she also found that this was the case. I joked with her that you probably could get a man to stand in the middle of the crosswalk this way if you were willing to push it far enough.
Men and women also tend to be different in how territorial they are. Women are far more aggressive in shops and men on the streets and sidewalks. If you're on a bicycle, for instance, women who are blocking the sidewalk are far more likely to move aside if you ring your bike bell whereas men are more likely to not move or to wait for a more aggressive second ringing before moving. Also, middle-aged and older men and women are far more likely to do these sorts of things than younger ones.
All of this territorial behavior is likely unconscious and I'm nearly certain it isn't Japan-based. I tend to think that it's part of living in a densely-populated urban area where you're constantly required to compete for space and attention. After you battle it for awhile, you may develop a second nature where you jockey for the best position without even thinking. I think I notice it more than others because I had no experience with it before coming to Japan and I tend to be incapable of tuning out what is happening around me.