Many people have told me, these last couple of weeks, that spring (when the fruit trees are in blossom) is the best time to visit Japan... but in spring you wouldn’t see scenes like this! Trees glistening with ice on the tips of their branches... magical.
In an onsen you start by taking a normal shower in a communal space (everyone bathes in the nude, with women and men in separate areas) so you’re clean. Next you enter one of the large pools, where the water is often partly heated by hot springs and “topped up” to around 40°C by human devices. In one place I went to, the water temperature was 52 degrees! I couldn’t stand it for more than about 3 minutes... but normally you might stay a lot longer in the water, half an hour or longer, trying the different pools. There’s bound to be some “proper” order to do with the different water temperatures, but don’t ask this ill-informed westerner ;) There is a pretty strict code of etiquette, though, often posted on the wall (and sometimes even in English!). Here’s an example: http://www.kashiwaya.org/e/magazine/onsen/rules2.html
Sometimes there’s a steam room, a sauna or a Jacuzzi section, and often there’s an outdoor pool (in fact, traditionally onsens were outdoor facilities). I loved the experience of the cold winter air above and the hot water below, and when you throw in the fact that an iconic mountain is right in front of your eyes, it’s pretty heavenly :) An extremely relaxing experience I can highly recommend! Most towns (even tiny) have a few onsens, and I got the impression that most people enjoy bathing this way a couple of times a week, if not more, for a few hundred yen a time (say £2.50).
Usually an onsen is a photo-free zone, for reasons of a) obvious modesty and b) who wants to sit their phone in a steam-filled room for half an hour?! But I was lucky enough, at Kirinosato Takahara later in my Japan trip, to have the onsen to myself a few times. So I did take a couple of snaps :)