I have lived and worked in Japan for some years now, and have found that the "workaholic" lifestyle isn't exactly what it seems. It is true that Japanese spend a lot of time at the office, however, the amount of work actually done is the same or less that what would be accomplished in an American or European office in an 8 hour workday.
The interesting thing about Japanese companies is that full-time workers receive strong legal protection, meaning that once you are hired, getting fired, or even demoted, is very difficult. Another thing is that Japanese companies promote by seniority rather than by performance. People who work hard will not be promoted any more quickly than people who work little. Since performance is not rewarded, workers don't bother to perform. Since workers don't perform, it takes more time to do a certain amount of work, and, worse yet, more workers must be hired in order to get work done.
As a result, Japanese companies tend to be overstaffed, wages are stagnant, and these companies have a harder time competing with foreign companies, whose workers are promoted and paid according to their performance. The very best and most ambitious workers in Japan prefer to work for "international" (which means not Japanese) companies.
My wife works for an American company which has a subsidiary office in Tokyo, which for years had been under Japanese management. The staff worked from 9 to 11 every day. One day, the Japanese managing director was fired, and a replacement from England put into his place. When the new director arrived, he was surprised at the long hours people worked, and even more surprised at how little work was actually being done. He then mandated that all employees would have to leave the office at 7pm, yet still do the same amount of work. The staff were horrified, and thought that it would be impossible to get their work done by 7pm. Many considered resigning, and began looking for jobs in other companies. But after a couple of months, they found that they could indeed get their work done in 4 hours less time than they had had before.