The U.S. is starting to show some reassuring signs that growth remains intact, and that's one element of comfort for investors to keep buying Japan.

Foreign investors are stepping up purchases of Japanese stocks and that is the main reason the market has held up so strongly in recent weeks.

Declines in commodity prices may cause investors to take a step back from shares of related suppliers.

While there are concerns about the slowdown in the U.S. economy, what's keeping investors optimistic is the expectation that the Fed is going to ease on interest-rate hikes. That's going to provide support for share prices.

There is a very real risk that Koizumi's plans to reform the banking sector will be so watered down that they will end up pleasing no one.

I think today's rise is no more than a technical bounce.