For many years, one of the lessons I conducted for my former company included the topic of "gambling". Over the years that I taught this lesson, I'd guess that I heard and read opinions from about 500 different people on this topic. The fact that the Japanese don't recognize how much gambling occurs in their culture wasn't the surprise as they can be myopic when it comes to acknowledging vice in their culture. The thing that was surprising was how many of them wrote long essays on the fact that they considered investment in stocks a form of "gambling."
In some ways, they did have a point. Like gambling, the stock market is something you put money into and hope will yield positive results. The students who equated stocks with gambling mentioned that it was akin to horse racing (which is a very popular form of gambling in Japan). They said that people who are relatively successful betting on the horses research them and know the smartest ways to bet to win overall. Additionally, certain horses with high odds of winning yield low winnings and the long shots yield high ones just as "safe" stocks offer low dividends and risky ones yield high ones. Finally, like playing the stock market, there is an element of dumb luck involved. There are people who invest smart, of course, but there are also those who just get lucky because the way the wind will blow in a particular market is hard to predict. And favorable winds that boost your investment's value could turn ill at any time just as that "sure thing" horse could have a slow day or stumble and lose.
Because of this attitude, most Japanese have generally been pretty skittish about investment in stocks. It's certainly not that they aren't willing to do the work involved in learning about it but rather that the lack of predictability makes them uncomfortable. One of my students did invest a small amount in the her husband's company's stock but she only did it as a small form of "insider trading". That is, she invested when her husband knew something was going to happen that had a nearly 100% chance of increasing the stock's value. She and her husband made about 100,000 yen ($880) then promptly divested before what went up had a chance to go back down. Their hasty retreat once a profit had been made lead me to wonder if one reason stocks aren't something Japanese people like to invest in is because you have to sell your assets at the right time or risk losing all you've "earned" should your stocks' value depreciate. I guess this offers another parallel to gambling. If you "let it ride", you might get more money, but if you're conservative and take your winnings and leave now, you may miss a valuable opportunity and regret it.
Lately though, there has been a market that some of the Japanese have grown comfortable playing in and that's the currency market. There's a growing number of housewives who have been chasing currency values in an attempt to boost their family's nest eggs. I can't say for sure why this is the type of investment that has drawn them in but I suspect it's because money is something they feel comfortable speculating on as it's easy to identify with. Even though the forces which shape the relative values of various currencies are complex and deep, I imagine that it feels more "real" and concrete than a company's business performance and market forces which affect their success.
It could also be that the Japanese have witnessed a lot of scandal and have been through a bubble which shows them so very clearly that what goes up, can come crashing down. After you've seen Japan move from a country associated with cheap junk to a point where it is perceived as having the greatest companies producing the best products in the world only to see it come floating down again as it was left behind in the tech boom of the 90's, you have to think that investing in the future of various companies is a gamble you don't want to take.