I was looking particularly hard for something that would allow one to move at a brisk pace, conserve energy and - above all else - be able to fully absorb the surroundings, being able to stop at a moment's notice and skip around on foot. So I had decided not to use public transit besides an initial departure from Tokyo.
A bike was the obvious solution. However, after reading extensively about Japanese bike laws, bicycle registration, air-travel bike regulations, train-travel regulations, bus-travel regulations etc I came to the conclusion that it is simply too much of a pain in the ass. I was considering buying a super-expensive and very tiny foldable roadbike to escape some of those regulations, but it was too much money. I had no idea at the time that OGWiz simply walked into a store, bought a second-hand mamachari for next to nothing, and went on his way. His idea was perfect and genius, and I wish I had done the same but suffered from a case of over-thinking it. Instead I walked - and walking is an amazing way of taking it all in, mind you - Just not with an overloaded backpack that is eating at your soul with every step you take. By the end of week one, I had massive blisters on all ten toes and heels despite wearing proper-fitting running shoes, and I was dragging my feet like a dead man along the surrounding rice fields. This was my biggest mistake and like OGwiz, I started throwing away anything I possibly could within a day or two. If I ever manage to go again I think I'll try bringing one of those small cruiser skateboards with me due to how practical it is. Then again, nothing really compares to buying a $40 used bike at the scene.
The bulky surplus water canteen and cooking pot were the first to go. Along with the fire starting stuff, and the rest of the survival shit. You really don't need to bring a canteen when you can buy a delicious 2L bottle of cold spring water/green tea from the convenience store and fill it up again from taps at Shinto shrines, mountain springs and public bathroom sinks. You also don't need, or want, or have the time to cook and start fires.
Gear-wise my biggest mistake was bringing a tent. I saved my money and bought an expensive, super-light tent for the trip only to find out that it was useless for the purpose. Too heavy, too big, too long to set up, too easily recognizable from a distance; These were all major flaws in one of the most imporant aspects of my plan. I somehow got incredibly lucky and only got two nights of rain showers, however I shudder at the thought of how unpleasant it would have been to set up or dismantle the tent during a proper storm: EVERYTHING would have been permanently soaked. A big problem was finding a place hidden enough to set up this bright red and white thing and nail it to the ground. This was especially difficult after sundown. A tent would be great if you plan on staying in a secluded place for days, taking it easy. Definitely not if you are permanently on the move. When I think of how much more pleasant my life would have been with a bivy bag or simply a bug net.. I hang my head.
Second, the sleeping bag. Another thing I saved a long time for and spent a lot of money on. Rated for down to 9 degrees Celsius. Much, much too hot for Japan in Autum. Many nights I tried not setting up my tent and just laying down under a roof or on a bench but the mosquitoes absolutely ravage your body. I'd try sleeping in my underwear but was still pouring sweat and unable to fall asleep due to the heat. So I'd end up half covered, half uncovered, half-sleeping, half-awake, half-getting eaten alive and half-sweating my balls off. I wish I had a bug net instead of a tent. Also I never managed to figure out how to find mosquito repellent anywhere I looked. I only found mosquito bite lotion. Not being able to rest properly after all that walking and sweating was very draining.
Third, the clothes. I tried extra hard to anticipate what I'll need and won't need as well as trying my best to maintain a semblance of presentable appearance. Cotton clothes take too long to dry when you're on the road in Japan, they also get too heavy. It's too humid and you sweat too much. I'd hang them up to dry at night and some mornings they felt as if they were actually wetter. What would really pay off would be investing money in tech sports clothing. Sports underwear would dry off within the hour, for example. Another very interesting thing I found out was that clothing made out of animal fibers like wool or silk would simply not smell bad no matter how much you sweat in it. I had two silk long sleeve shirts from the thrift store and they were great to protect from the sun and mosquitos in the forest but unfortunately silk rips quite easily and I ended up trashing both of them. I've read on the internet that you can get merino wool tees that have the same qualities of not smelling like shit. All you really need are 3 t-shirts, 3 undies, 3 socks and either one pair of long pants/one shorts or one pair of pants that zips down to shorts.
But yeah, they're very important and should fit comfortably and be able to take the abuse (and many washings in sinks and rivers) as well as provide protection. I anticipated I'd wear shorts most of the time but was forced to wear long pants usually, due to the mosquitoes again. My pants had some buttons awkwardly placed on the hips where the backpack waistbelt fit which wasn't a problem at first but after a week they left bruised lumps of flesh underneath them. Even something as simple as a belt shouldn't be overlooked. For example I had a cotton D-ring belt which became a heavy, soggy, slimy, rotten rope around my waist. Same would have happened with leather. You need to focus on light-weight, breathable synthetic stuff that doesn't retain water. Swim shorts were the best thing I brought with me, and were used almost daily for two weeks once I reached the coastline. Also an actual camera - make sure you bring one and not just your phone.
The backpack. The backpack might be the most important piece of equipment you own so make sure you get a decent one designed for backpacking and waterproof. I myself had one that was designed for bike couriers: Huge and waterproof and extra heavy duty but completely lacking any features and extremely heavy. I didn't buy a backpacking bag to try to save some money and it proved to be another mistake.
The heat can prove to be one of the most unbearable aspects of the trip as sometimes there will be no breeze whatsoever. You can look up at the highest trees and not see a leaf move while your blood boils. There are some incredible pieces of advice for this:
1. Convenience stores tend to stock up on 500ml water and green tea bottles in the icecream freezer in the Summer. Buy one, or two, and stick them inside your clothes or in between your backpack and back. I got severe heat stroke on my third day and after puking on the side of the road and crawling to a temple, the old lady there brought me back to life with this. Green tea also serves as a natural energy drink.
2. In Japan you can find these promotional hand fans all over the place. Acquire one as soon as you see it and hold on to it for dear life. Trust me.
3. If you find yourself in need of purchasing a convenience store umbrella during a downpour you should opt for the black ones as opposed to the see-through ones. The black ones can be used to provide portable shade in the scorching Summer midday sun. You'll be thankful for this when walking through endless ricefields.
I think that's all the biggest mistakes I've made that I can think of. I could write a hundred times as much about how amazing everything else was. If you avoid these you should be having the time of your life.
I can also make some notes on personal hygene since I like to be a clean homeless person. It's pretty easy with some careful consideration. It will be hard to bathe every night. In more popular locations you can use your phone or ask for public baths which are cheap and amazing and should be considered an absolute treat. The rest of the time you have to get creative. Wet wipes, especially those marked as facial cleansing wipes, serve as a portable shower in a pinch. With one single wipe out of the pack you wash your face, armpits, balls, and asshole (IN THAT ORDER). I strongly recommend you bring some along. As long as you find a place to wash your pits and nether regions every day you should be okay.
There are streams, there are public washrooms with sinks. These can also be used to wash your clothes and you should be washing a set of clothes almost every day so you always have a dry pair ready to go. For this purpose you should bring some kind of potent natural all-purpose soap like Dr. Bronner's which can be used as detergent, toothpaste, shaving cream, body and hair wash. With a small mirror you can shave in a puddle of rainwater. There are coin-operated laundrymats in bigger locales but as a warning the machines there are ancient and use gas-powered dryers that will fuck up your clothes and maybe shrink them twice their size, use at your own discretion. If you don't have the time for your clothes to dry figure out how to clip them on to the outside of your backpack while you're moving.
Oh yeah, and keep plenty of room for your garbage. It could be a while before you can get rid of it. I had the bad habit of picking up other people's garbage along the way so most of the time I'd always have two plastic bags full of trash clipped on to the outside of my backpack, which I imagine made me look even more homeless. Such is life.