Historically, derivative suits by shareholders were rare in Japan.

A derivative suit is slow, inefficient, risky and potentially expensive.

The shareholders' action is technically called a "derivative" suit, in which the shareholders act on behalf of the company.

The plan's authors say it would still be hard to bring derivative suits for violations of the duty of care - negligence cases.

"The knowledge that derivative suits can be brought is a very strong control over corporate conduct."

Just how useful or damaging derivative suits are is the subject of much debate in business, academic and legal circles.

The mere threat of a derivative suit can also deter illegal corporate behavior, plaintiffs' lawyers say.

While legal fees are typically low in derivative suits, there have been a handful of cases where plaintiffs' lawyers walked away with millions.

Part of the growing interest in derivative suits may result from the fact that business, and fees, are down.

This marked the development of the shareholders' derivative suit.