Yesterday one of my students showed up for her lesson sporting newly-dyed medium brown hair. Her hair was black before but she thought that brown hair looked "cooler". The brown looked quite flattering and suited her skin tone well and I complimented her on the change.
While it may not seem like a big deal for someone to go from having black hair to brown, it is a sizable transition for a Japanese person and it isn't something that is wholeheartedly approved of by everyone. My student works part-time at a well-known Japanese casual wear retailer and she told me that they don't allow employees to have "light" hair. Her employer believes that customers are uncomfortable with those with brown hair because they'll perceive them as "rude" or believe they have bad attitudes.
On the one hand, the conservative posture that her employer is taking is somewhat surprising considering how many women in Japan have brown hair these days. It's not exactly rare or shocking. On the other hand, it does fit in with some of the stories I've been told about how small variations in appearance can get kids bullied in school because of the expectation that everyone should be very similar in appearance. One of my other students told me that she had slightly wavy hair as a kid and was teased mercilessly for it. To this day, she always has her hair regularly straightened because of what she went through as a kid.
Since the student who works part-time at a casual wear retailer has a head full of long brown hair now and she doesn't want to quit her job (or get fired from it), I asked her what she was going to do. She pulled a white tube of something out of her purse and showed me her "instant retouch". Unscrewing the cap revealed what looked like the top of a shoe polish applicator. She told me she rubs this goop on the top of her head to darken her hair before work and it washes out when she takes a shower. It seems like a lot of trouble to me, but I guess it's the price she's willing to pay in her working life as a retail drone so that she can be more of an individual in her private life.