Is it better to travel with a companion or not to travel with a companion in Japan?
I'd say firstly, it depends on your attitude and level of Japanese. Also, it depends a lot on how you typically travel. For instance, if you travel an average of once or twice a year then by all means bring someone with you for good company and to enhance the experience. But, if you are cataloging your experiences, and spending a lot of your time immersed in writing and photography then in my opinion going it alone is far better than with someone, unless you are climbing Mount Kilimanjaro or going on a dangerous expedition somewhere.
The soloist is a guy who isn't looking for the romantic get away spot. He/she is in search of information and contact with other people. He wants an intimate experience with his surroundings only. I want to feel my camera in my hands. I want to feel and smell every single tiny little blade of grass I walk over. I want to get a feel for the whole of nature while totally caring nothing about anyone else. That's the soloist.
The soloist is the type of guy/gal who can linger around in a hot spa for ages and not be pressed for time, because of dinner appointments or scheduling complications. He or she can also spend as much time doing absolutely nothing at all and not offend anyone else while doing it. The soloist remembers what was eaten for dinner because it was the food that was communed with, and not necessarily with a stranger who would rather talk the experience away with redundant question about where I am from. The soloist has muted his anxieties from the constant stairs from the packs of elderly who sees him or herself sitting in golden silence and wonders why and how someone could achieve such a peaceful state of bliss. There is nothing as wonderful like existing in such a peaceful state.
I learned this from Mr. Takayama-san years ago. He and I had absolutely nothing in common. Whenever he took me out to a natural hot spa he rarely spoke to me. He was a man of few words and never wasted his time on gossip or adult related topics. He would just look over at me and say " that is low energy!" I began to pick up a lot from him because he was the lone traveler who showed me the way. In modern societies most people would rather settle for the conveniences of home rather than going out to stay in a hotel. This is a natural consequence of modernization. In other words, people have forgotten why people go out anymore and this is not good. There is just simply no comparison with your home bathing unit to a natural hot spa spring in nature.
The purpose of this post should not be taken to mean "you should travel alone." I just feel I need to lend some perspective on travel from a guy who travels solo sometimes, for the sake of clarity if anything. Being a soloist can sometimes be dangerous like when I drove through a snowstorm from the Tokachidake Mountains of Hokkaido to Sapporo and my GPS was out and with no visibility and on an unmarked road.
In another instance is when I got stuck up on a mountain at midnight and saw howling wolves encircling my perimeter from the headlights. I was able to clear just enough room on the road from a fallen tree to edge my car through and made it to safety. I haven't blogged about that experience until now I think.
What you have to take from life's lessons is that time waits for no one. You have to make your own moves and then people will help you along the way. Not " I'm going to wait for people to show me the way." Maybe for some people. At any rate, to solo or not to solo is a decision that you clearly have to make based on your needs, and what your purpose is. If you are the carefree type that's not too caught on travel and need a companion then by all means bring a buddy or two. I have travelled in groups and have enjoyed myself immensely.
What you need to bring with you if you do decide to travel solo is good dictionary, travel guide, extra batteries. At every station I like to check and recheck that I have everything I need. If you bring a laptop, then a good USB connector for it is a must if you need to charge your phone. Most convenience stores carry generic chargers, but are very poorly made and do not charge your electronic devices sufficiently.
Try not to feel overwhelmed by your surroundings. Keep a cool head and always act as if you are an experienced traveller, and try not to look like someone who has never travelled in his/her life. Looking stoic is better than appearing totally lost. It's because you do not want to attract the wrong kind of attention, unless of course if you are really in need of help then that's another story.
I find the Japanese people to be warm and hospitable, and very accommodating. Some have a reasonable command of the English language whereas others absolutely none. In another experience, when I was visiting South Korea, I went into a Korean BBQ restaurant by myself and was refused entry based off of how I looked, so I thought. The lady says "Japanese only." "But this is Korea!" I answered back. What she was really trying to say to me was that in her restaurant they only service customers who either speak Japanese or Korean, in which case I speak Japanese. After conveying this to her she seated me and provided me with excellent customer service; the food was great too. It was the language barrier she was afraid to confront which is what I find in many countries I have visited, in that it is not so much about how you look, but what language you can communicate in. English is not entirely the key to unlock all doors.
When travelling solo, I highly recommend having a reasonable understanding of the host country's language, or at least bring a language book. A nice smile wouldn't hurt either. People are generally kind in many east Asian countries, even to the soloist.
When travelling in Japan you will also find that the Japanese are very open, and are more than willing to accommodate you whether it be at a hotel or a restaurant. However, I do not advice visiting the red light district because these areas are exclusive 'Japanese only' establishments ran by the mafia, and other seedy organizations.
The thing to remember here is that even though Japan is relatively a safe country, you still need to avoid areas where you suspect there may be danger. Other then that, enjoy your trip to Japan. There is a plethora of information on Japan on the internet, and you could literally spend hours wading through recommendation after recommendation as to where to eat and go. In the end, I recommend following your best judgement and enjoy your stay in Japan.