Japan has a sleeping @ work culture. But before we conclude that the Japanese are slacking off, it helps to understand a bit about Japanese culture first.
Many Japanese pride themselves on work extremely hard. They do not easily accept anything less than perfect, so this perfectionist mindset often lends to a great deal of personal fatigue Not only this, but on top of frequently pushing themselves to exhaustion they will work extremely long hours. School teachers in Japan work 12 hour days on average. Salary men (business men) in Japan will work around 10 and 12 hour days on average.
In fact, Japanese are so work obsessed that the idea of being a dedicated workhorse dictates how they use their language even.
As Japan-Talk.com points out:
"When people say goodbye to their coworkers in the evening they don't say "have a nice night" or "have a nice weekend". They say "otsukaresama deshita". This can be literally translated as "you are tired sir". It's the nicest thing you can say to someone — that they are tired."
More than this perhaps, is the fact that sleeping while at work is also largely considered a statement. It's a statement about the long hours you put in, the amount of work you are doing, your status in your company, and how indispensable you are (more on this in a moment).
There are other contexts for inemuri as well.
College students who cram for exams will often pull all-nighters just to study for a single test the following day. Having taken the exam, the remainder of the day will be utilized to catch up on their much needed sleep. Usually doing a bit of inemuri in each of their subsequent classes until school is out, at which time they will pull another all-nighter as they cram for tomorrow's next big exam.
High school students can be seen power-napping on the train to and from school. Many high school students in Japan head to school on the train at 6 and 7 am. They go to school all day then head off to club activities till 6 pm. In the evening many will power-nap on the train as they head to their juku (after school-school/evening school).
Vice principals of public schools in Japan have one of the toughest jobs. Often times I will catch my vice principal at my JHS in the act of inemuri. He is power-napping because he has the responsibility of opening the school in the morning at 6 am sharp as well as the responsibility for locking up the school after the last teacher has gone home at around 10 pm--on top of the nonstop work he has to do every day.
In Japan it is normal to see people pass out due to exhaustion. I see co-workers or students suffer from exhaustion on a weekly basis. While it certainly isn't healthy, they proudly wear their bouts of exhaustion like a badge of honor. Passing out from exhaustion isn't a sign that you're weak, it's a sign that you have pushed yourself to the limit and were only defeated by the fact that you're not a tireless robot.
Inemuri is usually seen as a good thing in Japan. It means you've been working hard, and so most of the time people leave the power-napper alone. But not just anyone can get away with sleeping at work.
Sleeping at work isn't just for the overworked, it's also a sign of who carries the highest amount of respect and most important or vital position. Napping during meetings is also common. But it is often hard to tell whether one is engaging in a bit of inemuri or if they simply are trying to concentrate hard. In Japan, making eye-contact is not a form of social etiquette, so closing ones eyes to listen intently isn't viewed as disrespectful like it would in a big corporate meeting in the west. Japanese politicians will often close their eyes and bow their heads in meetings to listen more intently to what is being said (see above picture). Although sometimes they do fall asleep while trying to focus, but because of their high position and important status, it often will be written off as a harmless bout of inadvertent inemuri.
Needless to say, the higher up the chain of command you are, the more likely you are to get away with a bit of inemuri. Your boss, for example, is more apt to be caught napping than anyone else. The head of an entire division at the company or BOE will also likely be able to get away with some inemuri. Getting away with it, so to speak, really depends on whether or not you are indispensable to the company. Many office workers who do not have position or privilege will wait until their lunch break to nap at their desk. Others will wait until they get on the train to let themselves catch a little nap, which is why you can frequently see salary man sleeping next to high school girls (both engaged in inemuri).
In other words, you have to earn the right to power-nap in Japan by not only working hard but making a big show of it. Personally, I find it all too much work, and far too exhausting, which is why I've never felt the urge to power-nap at work.