I have come to Tokyo on my own as none of my friends had the time, money or freedom. I LOVE IT!!! but I am a male
I have had lonely times or rather times I would have liked to experienced with another but I have also had some great times and made great new friends.
I am a Londoner and have felt as lonely and lost in London some times but at least they speak English. But what the hey! Language does not have to be a barrier.
I have the fortune of living in a guest house where many of the other residents are Japanese working people, we have only a few gaijin here. I have always put myself out to communicate and help my fellow residents to make a better community and this had paid off well.
There are a group of us guys that now go out for a meal and drink on a sat night 5/6 of us depending on who has work and the girls floor has just offered to take me out for a meal and drink.
I have found a good local bar where I now have my own Japanese mom who is a master karaoke singer (after a few drinks), she introduces me to the locals and we are going out for a meal next week.
I have made a good English friend over here who is married to a Japanese wife and I am going to their barbeque next weekend in Chigasaki. I have met a cool American guy in the block next door who might be able to find me a job here as he recruits westerners. I have had so much fun it hurts and I still have until the end of June. Oh! plus I have been through a 6.2 RS earthquake and it was soooooooh cool!
For me the key factor is showing respect for your fellow human and in Japan you get this repaid in spades. In London this is seen as weakness and to be taken advantage of as in many other western places. In Tokyo I feel like a human but in London I felt like a number.
I do not regret coming here alone for one moment and would make the same choice a thousand times over. I just wish I could speak Japanese so that my trip would have been so much better but I am just a stupid gaijin having many good times.
Marc.