Japan's crown prince says hasn't read book on wife

TOKYO, Feb 23 (Reuters) Japanese Crown Prince Naruhito said he hasn't read an Australian book about the plight of his wife, Crown Princess Masako, that sparked government protests for what Tokyo says are factual errors and insults to the royal family.

But Naruhito told a news conference that while Masako was slowly improving, a full recovery from the mental illness that has kept her from most official duties for more than three years would take more time.

Publisher Kodansha Ltd said last week it had cancelled plans for a Japanese edition of ''Princess Masako - Prisoner of the Chrysanthemum Throne'', prompting Australian author Ben Hills to complain that the Japanese government had censored his work.

Hills said in the book -- which he has described as ''an Oriental Charles and Diana story'' - that 43-year-old Masako, a Harvard-educated former diplomat, was suffering from severe depression, not a mild ''adjustment disorder'' as described by the Imperial Household Agency, which manages royal affairs.

Japan's Foreign Ministry has sought an apology and ''appropriate steps'' from Hills regarding the book, but has declined to comment on specific aspects such as his assertion that her only child, Princess Aiko, may have been conceived through in vitro fertilisation.

At a news conference to mark his 47th birthday on Friday, Naruhito sidestepped the furore.

''I have not read the book, but I have heard about it from my household staff, so I think I have an understanding of its contents,'' he said.

''Since the government is handling the issue, I will avoid further comment,'' he added, according to a transcript of the news conference released on the agency's website.

AVOID CONTROVERSY Japan's royals usually avoid controversial comments, but Naruhito set off shock waves in May 2004 when he told a news conference that Masako had exhausted herself trying to adapt to royal life.

Masako has been unable to perform most of her official duties for more than three years due to the illness, which royal watchers say was caused by the stresses of rigid royal life, including pressure to bear a male heir.

Tabloid magazines frequently discuss royal issues that the mainstream media tiptoes around, and last year even speculated that divorce might be an option for Masako.

The prince said that Masako was getting better but needed to regain confidence before she could resume all her duties.

''Masako is making as much effort as possible, and slowly her condition is improving. But she still tires, and the doctors say how much she can do still must be judged on a case-by-case basis.

''I would like to ask the Japanese people to understand the situation and watch over us from a long-term perspective.'' Naruhito also spoke tenderly about Aiko's activities, but declined to comment about the chance of another child.

Only males can ascend the throne in Japan. The birth last fall of Prince Hisahito, the first male born in imperial family in more than 40 years, shelved plans to change succession laws.

The Imperial Household Agency has denied pressuring Kodansha which said it scratched the plan for the Japanese edition after Hill refused to apologise for errors that had been corrected with his consent before the Japanese government's protest.

Reuters SSC DB093