The Imperial Household Agency has said, enigmatically, that 'some people' can become temporarily unable to speak after suffering 'great grief'. The Empress is now attending public functions again, and last week she used sign language to communicate to disabled people at a welfare centre. But still she remains mute.
The secretiveness of the Imperial Household has made any outside medical assessment of her condition difficult, although suggestions that she had suffered a stroke were denied. Yet the Empress does not appear to be ill, in any normal sense of the word.
Conventional wisdom suggests that she was distressed by a number of critical articles sniping at her lifestyle in the Palace. Over the past few months, anonymous Palace insiders have supplied magazines with petty details of how she has allegedly ordered servants to prepare snacks for her in the middle of the night, how she changes her clothes several times a day, and how she supposedly dislikes the uniforms of the soldiers who guard her and the Emperor.
Compared to the recent revelations about the Prince and Princess of Wales's stormy marital break-up in Britain, the stories in the Japanese press look like a Ladybird books version of royal troubles. There is clearly more to the silent grief of an Empress than a few trivial gripes from Palace retainers.
In a sense, the Empress has been struck dumb by a simmering conflict in which she is little more than a spectator. For there is a split between those in the Palace which believes that the Imperial Family should be closer to the ordinary people, and those who want them to remain aloof from everyday life, as an unchanging, quasi-religious institution upholding the myth of Japan's descent from the sun goddess, Amaterasu.
As the first commoner to be married to a Japanese Emperor, Michiko has acted as the lightning rod of discontent for those traditionalists.
The battle lines for the latest conflict were drawn up in 1990, when the Emperor Akihito was enthroned after the death of his father, Hirohito. Although Hirohito had disavowed his divinity on the demand of General MacArthur after the war, he remained remote from his people.
By contrast, Emperor Akihito and Michiko have made it clear that they favour a more open approach. And, to add to the traditionalists' dismay, the new Emperor has made trips to China and South-east Asia, where he has offered words of regret - if not outright apologies - for Japan's wartime behaviour.
In an article published this week by the Shukan Bunshun, a weekly magazine that had been one of the main critics of the Empress, the confrontation is brought out into the open. Under the guise of printing an apology to Empress Michiko, the magazine gave a long description of the 'crisis' it claims is now affecting the Imperial institution as it seeks to redefine its identity. The implied message was: does Japan want to popularise its Imperial family and risk sacrificing Imperial dignity, the way the Windsors have suffered in Britain?
While this squabbling goes on, Empress Michiko could be forgiven for remaining silent.