The summer months in Japan can get pretty rough, so it's a bit tricky figuring out what to pack to stay cool, but also not attracting any disapproving stares. Luckily, you won't be held to the same standards as Japanese citizens, so don't stress if you slip up!
How Short is Too Short?
Japan is a leg country, you can wear the shortest skirt and the shortest shorts that you have and still be OK in terms of casual wear. This type of casual wear is more commonly seen in major cities like Tokyo and Osaka, as you get into more rural areas you may want to cover up a little more.
Certain areas like temples and shrines are holy areas and should be treated as such, so don't have anything hanging out!
Cleavage is a No-No
Japan is very conservative when it comes to the top half of a woman's body. The line on your chest that's considered "cleavage" is actually very high compared to other countries, so it might be a little difficult to find a nice shirt that isn't considered inappropriate while still trying to keep cool.
Luckily, you won't get arrested for showing a little chest. The most important thing is that you're comfortable in what you're wearing. Generally, just try to make sure that your neckline isn't too deep, and you should be alright. If you're worried about catching some unwanted stares you can also wear a tank-top underneath your shirt, so you won't be in danger of revealing anything if you bend over.
Can I Show My Shoulders?
This really depends on where you are in Japan. Often, you won't see Japanese women where anything that exposes their shoulders, so spaghetti straps and strapless dresses are rarely seen. This belief, however, is more commonly observed in rural Japan, and becomes less strict as you go into major cities.
Because Japan gets so hot and humid in the summer I wouldn't worry about exposing your shoulders. Don't sacrifice your comfort, and ruin your clothes, being a foreigner you'll get stared at anyway so don't worry too much.
Comfortable walking shoes are a must when you visit Japan as you'll be walking all day everyday. Pack a pair of comfortable semi-casual shoes, and leave the flip flops at home! Flip flops are not only uncomfortable to walk in all day, but are also unfashionable in Japanese society. Sandals are the preferred choice if you want to wear open toed shoes, but I wouldn't suggest bringing these since they don't support your feet at all.
If you plan on going for a night out pack a pair of fancy dress shoes like flats, heels or loafers. Try not to overpack, one pair of walking shoes and one pair of dress shoes should suffice for your visit.
What About the Men!?
You've probably noticed that this article was more about the do's and don'ts for women rather than men. Men's fashion doesn't really change, and most of what mean wear isn't seen as provocative to others.
Overall, just put some effort into your daily outfits. Don't wear shorts that resemble pajamas (sweatpants or basketball shorts) or that are so loose that your underwear peaks through. Men's tank tops are uncommon in Japan, so you may turn some heads if you decide to show off your arms.
In conclusion...don't worry too much! Japan is known for their oppressive summers, so dress comfortably, it's better to show a little skin rather than ruining your favorite t-shirt with your sweat.
3. https://i.ytimg.com/vi/09yoCNdx79c/maxresdefault.jpg (cover photo)