Firstly, the famously difficult exam that you have to take to become a barrister in Japan is set by the Bar Association, ie practicising lawyers, who obviously have good financial and status reasons for keeping the number of lawyers as low as possible. Another factor is that many of the top law graduates in Japan have no intention of becoming barristers because getting a job as a public servant or in a large company is more common and traditionally at least as high status. The third factor is that many of the things done by trained lawyers in the US etc are done in Japan by the aforementioned people in government and business, as well as by scriveners, notaries, patent clerks etc. The well known cultural difference theory that Japanese don’t like sueing each other is probably the least important element.
And to illustrate how few there are, a little bit of Japan by Numbers:
21- The total membership of the Shimane Bar Association in 1995.Of those,3 were not active,leaving the whole prefecture with only 18 practicising lawyers