If you go to Japan you will soon get used to the smell of cigarette smoke, since it is more or less everywhere.  It's unavoidable, so travelers must learn to deal with it.

There are some reasons why Japan has done nothing about smoking. First, the government is basically a partner with the tobacco industry and it generates a major source of revenue for the public coffers. Second, with respect to social issues, Japan is probably 20-30 years behind the United States. Third, smoking is viewed as a right, not a privilege and the right to pollute others' airspace is sacred. Lastly, tobacco-related rates of death among smokers are lower due to the lack of obesity in Japan which lessens the likelihood of cardiovascular complications (much less tobacco-related heart disease). The healthcare costs are not so burdensome.

What can traveling non-smokers do?  Very little, is the consensus.  Restaurants rarely have any smoking areas and you may well find everyone at the next table smoking furiously throughout the meal.

This is definitely a problem when you stay in a ryokan room that's just been vacated by smokers. When making your reservation, ask about the room and, many times, they willl "de-odorize" it before arrival.  (This means spraying the room with air freshener or something similar before check-in.)  However, people who are really sensitive to cigarette smoke will probably still notice the smell.

When traveling by rail, make sure to book a seat in the non-smoking car on the Shinkansen.

Avoiding pubs, restaurants, concerts, outdoor events and walking in crowded outdoor areas is one way to avoid smoke but it's pretty restricting if you need to do this.

Note:  The original information for this thread came from the   following forum thread: