I visited the bookstore today to look for a design book and in passing the finance section was surprised to see how many books were being published to help people understand FX trading (Foreign Exchange Trading). FX has been big in Japan for some years with quite a lot of bad press being attributed to those who have made a lot of money but not properly declared it on their income tax returns.
I am guessing the average person would probably lose more than they make, and therefore to assist them these books have become very popular.
There were many books available, both written in manga style as shown in the first picture to the more serious books below.
In particular the currency pairs of USD/JPY and EUR/JPY are popular in Japan. Before the current economic crisis many Japanese also had their eye on NZD and AUD because of the large differential in interest rates between New Zealand and Australia versus Japan.