Now that you’ve decided on picking up a car and shopped around for one, this guide is dedicated to information about preparing yourself for winter driving in Japan. (Insert obligatory Game of Thrones “Winter is Coming” meme here.) For many of those who come from snowy regions, much of this will come as second nature. (Especially Nordic folk… you guys birth all the great rally drivers, after all.)

Winter Preparations

Winter wheels / tires
When temperatures drop, many areas in Japan require the use of winter tires instead of the so-called all-season tires. “All-season” sadly doesn’t actually mean for all seasons, as the name might imply, as they lose their effectiveness when temperatures drop below 7°C (45°F). Colder temperatures harden the rubber compound, thereby increasing braking distances and losing traction, obviously making driving significantly more dangerous. Beyond having a softer compound in the cold, winter tires also have sipes, channels, and grooves which push away water, increase tire temperatures, and (surprisingly!) hold snow.

It is best to buy a set of winter tires with wheels (the metal round inner part) installed on them, as it makes much more economical sense to buy them together when you have to switch back and forth through the year. Buying the winter tires only and putting them on the wheels the car has now might be marginally cheaper the first year, but will soon add up after. For example, you can find a basic set for kei cars for less than 40,000￥. Swapping them on the car costs usually only about 2000￥ at your local gas station. Compare this to the 20,000￥ for the winter tires alone, which will cost 8000￥ every time to swap them on your existing wheels, plus the 2000￥ for installation. So at 16,000￥ in wasted labor costs the first year alone, it makes sense to pay that little bit more to get them as a set.

Common winter tires are often also called “studless” because most winter tires do not have metal studs in the rubber compound, which are rarely used for heavy snow traction, since they destroy pavement. Winter tires should also be purchased at the same or smaller size than the car is driving on at the moment. For example, my white plate car can drive on 205 width tires, but it is recommended to use 195 due to the thinner profile. This helps it “dig” and cut into the snow better with the smaller surface area.

If you don’t know what all this means, don’t worry. Ask your local car guy or tire shop. They probably won’t steer you wrong.

This is the coolant reservoir tank… you can see it’s a bit low here.

Engine
Of course, you should check your car often to ensure fluids and engine operation are good. This goes doubly in adverse weather, summer and winter. In winter, the two most important things to check are the radiator coolant / antifreeze and wiper fluid. While the balance of coolant to antifreeze are balanced when filled by mechanics, it is a good idea to check the fluid level as low levels of fluid could lead to frozen engine blocks. Some people only use water for wiper fluid and while this is fine for most of the year, frozen water in the wiper fluid pipes could lead to busted old hoses that feed it to the nozzles. So be sure to top off with proper wiper fluid, which are mixed to resist freezing.

Not related to the engine, but still important, is the condition of the wipers. Make sure your wiper blades are functioning well and not falling apart. Old blades tend to get brittle and fall apart faster in the dry cold and the last thing you want is to drive blindly in a snow drift with the metal wiper arm dragging against your windshield.

Items to Have
Personally, I like to keep my interior and trunk pretty clean with only the necessities I might need while travelling, such as a small umbrella for the freak rainstorms, a small medical kit, hand wipes or disinfectant, and a folding eco shopping bag. I don’t try to keep too much else in the car, but during winter I will add a few more items.

Squeegee: The extendable squeegee I use has a soft foam head, a rubber wiper blade, and a plastic flat end. Each end serves a different purpose, as I’ll describe down in Driving, below.

Gloves: While it’s probable that you’ll already be wearing gloves in the winter, it doesn’t hurt to have an extra pair in the car, since after all that shoveling and squeegeeing your windows, it might have gotten a bit cold and wet.

Shovel: This might be obvious, but it’s good to have a shovel in your car when a random snowdrift hits you when you aren’t at home (where your shovel usually is). A few hours of snow really piles on quick and will be quite troublesome to move without a handy shovel.

Insurance
Lastly, check your insurance to see if you have roadside assistance coverage. Some insurance plans do have it as part of your package. If you don’t, I highly recommend you sign up for JAF, Japan’s automobile association. For only around 4000￥ a year, you can have roadside assistance if you lock yourself out, run out of gas or battery, or need emergency towing. (This is an unpaid advert for them.)

It’s better to have it than be without it on a cold, snowy night stranded in a ditch somewhere. Take it from me, if you don’t have the coverage, be prepared to pay a significant amount for a small tow.

Driving

Starting off, if you have some snow buildup, wipe and scrape off the snow with your squeegee. Do not use the rubber or plastic ends on your car body, as any rocks or debris will scratch your paint. I use the softer sponge end and only apply light pressure, if I touch the body at all. The rubber end is best for your windshield to remove water streaks and the plastic end is for scraping stubborn ice. To further rid yourself of icy windshields, contrary to some idiotic bits of advice online, do not pour boiling hot water directly on your windshield. Have you ever seen what happens when hot water hits an extremely cold object? It may be extremely unlikely on tempered glass, but any pre-existing cracks may widen with the sudden thermal change. I personally use warm water so the temperature differential is not as great, but will still work wonderfully to melt the hard ice. Wipe and scrape off the remainder of your ice with your squeegee.

While it might take a bit of extra time, push off as much of the snow off your roof and hood as you reasonably can. If you brake hard, that snow can fall back on your windshield at an inopportune moment, temporarily blinding you. Also annoying is that snow buildup may freeze overnight and make it difficult for you to open your doors the next morning.

They’re hard to see, but there are actually open water drainage ditches in this photograph.

Watch for ditches, tiny roads, rough snow plowing, obstacles, black ice, and heavy snow piles. Especially in rural areas, “gaijin trap” water ditches are common. (Actually, they are called ryuusetsukou or snow drainage ditches.) You may forget about them on your regular route, but when it snows, the points of reference change greatly so where you think the edges of the road are may not be so. Drive with care and moderate all your driving inputs: accelerate slowly, brake gently (if possible), turn in gradually. Sudden dramatic directional changes will upset the car and make it more likely the car will break traction.

While soft snow is little more than a nuisance, icy roads can be dangerous. Melted and refrozen snow might look safe to drive on, especially if the road is heavily trafficked, in actuality it is extremely slippery. Keep your following distance from other cars much farther than you might typically, as braking distances will increase significantly. If possible, take larger roads because they often have road sprinkler systems (shousetsu pipe) installed. Essentially, water is pumped up from warmer underground sources and sprayed seemingly haphazardly all over the road and your car’s windows are inopportune times. You might think watery roads are less safe than a seemingly clear road, but those sprinkler systems melt snow and remove ice, thereby making driving much safer. Just keep your wipers on and don’t be surprised at the sprays hitting your car when you drive on them.

Another form of icy roads comes as “black ice.” It is a generally rare road hazard, but more common in the dead of night in the middle of the rice fields. Essentially, black ice appears on asphalt that appears to not have any snow or ice on it, hence the term. In actuality, there is a fine layer of water that has frozen over the pavement, so it might not be perceivable. I have personally seen two cars fallen and stuck in the rice fields late at night due to the surprisingly slippery road conditions that look otherwise clear. As with the advice above, drive slowly and carefully, though even more so if you see the shine of a wet-looking surface: it just might be dreaded ice.

Lift your windshield wipers when you stop for any extended period of time overnight. This might look silly, but there’s a reason everyone does it: it prevents the wiper blade from freezing to the windshield and at the very least makes it easier to remove ice and snow in the morning.

One last thing to note, make sure you do several underbody car washes when the snow starts to melt and dissipate. (Most gas station car washes have the option.) In some parts of the country, they salt the roads here with calcium chloride or sodium chloride to reduce freezing. (In my part of the country, you can find green metal boxes along the side of the road with bags of white stuff for this expressed purpose.)

As a result, some of this stuff gets under your car and around your wheel wells. The salt buildup underneath your car will start to eat away at the minimal (if any) paint and protective coatings, accelerating the rust process. Most of these kei cars do not use galvanized steel, so they are quite rust-prone. Washing any loose salt, rocks, debris, etc from your undertray (and the rest of your car, for that matter) will go a long way into preventing this.

Enjoy the gorgeous winter wonderland in the snow and drive carefully, folks! As always, drop me a line if you have any suggestions or questions.

Edit: Thanks to Megan for some additional information!
Edit 21/01/20: Added information about salted roads