Among those advising company board members on how to handle activists are Morgan Stanley and Bank of America Merrill Lynch. Two other banks, who declined to be named because of the sensitivity of the issue to clients, also told Reuters they were coaching Japanese executives on engaging with such investors.

Japan was the top destination in Asia for activist campaigns last year, with its companies the target of a third of all such campaigns in the region, according to a report by JP Morgan.

The trend of firms seeking advice shows a shift is underway in Japan's attitude toward activists. Its companies have long held a reputation as a graveyard for investors demanding change, with activists traditionally viewed by boards as asset-strippers to be resisted, not legitimate investors with whom to engage.

"It is like a regular medical check-up – we do it regularly for Japanese clients even before they are approached by an activist," said Akihiko Manaka, head of Japan mergers and acquisitions at Bank of America Merrill Lynch.

"We offer Japanese clients analysis to look at the industry benchmark in terms of financial statistics as well as corporate governance and shareholding structure."

A sense that executives are increasingly prepared to listen is encouraging more activists to join the fray, analysts said. Last month, U.S. hedge fund ValueAct Capital announced its first-ever Asian investment with the purchase of a $600 million, 5 percent stake in Japanese medical equipment and camera maker Olympus Corp. ValueAct tends to avoid public battles with companies in favor of closed door-discussions.

And Elliott Management has taken a stake of more than 5 percent in Japan's Alpine Electronics and plans to make significant proposals, according to a filing by the activist U.S. hedge fund last week.

That comes after Hong Kong-based activist fund Oasis Management objected to the components maker's sale to a bigger affiliate.

POLICY, VALUATION DRIVERS

Investment banks aren't the only ports of call for Japanese companies preparing to deal with activists. Three public relations firms described to Reuters growing demand for such services.

"We have done a lot of work with companies on vulnerability assessments, helping them proactively assess where they may be susceptible to activist demands before an activist arrives or begins agitating for specific changes," said Nicola McGowan, managing director at Finsbury Japan.

Activists have also taken heart from corporate reforms driven by the government. A governance code introduced in 2015 and updated later lists situations when boards can consider ousting a chief executive - a key shift in Japan's non-confrontational working culture.

The potential to untangle a web of cross-holdings and a corporate tendency to hoard cash have also attracted activists, as has Japan's relatively low valuations. The blue-chip Topix 500 is trading on 14 times earnings, according to ThomsonReuters data, compared with 22 times for the US S&P 500.

"Japan is the ideal target place – there's so much value to be unlocked," said Zuhair Khan, an analyst at Jefferies in Tokyo, who said the lingering tradition of cross-holdings could make activists' task tricky.

Examples of successful activism at companies, especially bluechips, remain rare in Japan. And even in cases where change does happen, firms rarely acknowledge the role played by activists.

In 2015, Japanese robot maker Fanuc Corp raised dividends and stock buybacks after demands by activist investor Daniel Loeb for better shareholder returns. Fanuc said at the time it was responding to the government's push for better corporate governance and not to Loeb's demands.

And activist hedge fund investor Daniel Loeb’s Third Point failed in 2013 to get electronics and entertainment firm Sony Corp to partially spin off its entertainment business.

STEPPING IT UP

Still, emboldened by the government's governance push, activists have become increasingly vocal in their demands for change. The shift is forcing companies to look at how to deal with activists before as well as after they propose changes, bankers said.

Seth Fischer, founder of Oasis, whose campaigns have helped produce strategic change at Nintendo Co and raise the price Panasonic Corp paid to take a unit private, has over the past 18 months used more public tactics to push companies for change.

"Every engagement starts soft but if we don't get meaningful dialogue, we escalate to writing letters, then setting up websites and maybe going as far as proxies and lawsuits," he said.

"Companies are engaging more and they're asking banks to help them figure out how to address our concerns - which hopefully means they'll meet us somewhere in the middle."

(Writing by Thomas Wilson; Additional reporting by Jennifer Hughes in Hong Kong; Editing by Muralikumar Anantharaman)

By Thomas Wilson and Ayai Tomisawa