Friends and successful hedge fund managers Guy Spier and Mohnish Pabrai both assembled a basket of Japanese "net-nets" for their respective portfolios a couple of years ago.
The results of those investments were not sensational according to Spier with the depreciation of the yen offsetting gains in stock prices.
Spier thinks that the language barrier and corporate culture in Japan make investing in Japan very tricky. In Japan it is basically impossible to influence the management of companies.
Spier likens this to flying blind, and he doesn't think he will again invest any significant amounts of money in Japan.