The Tennō and Empress were out of Japan to make state visits to the Netherlands and Belgium from June 13th to 26th. The visit to the Netherlands reportedly involved the King and Tennō sitting down together to watch the Japan-Netherlands match at the World Cup, so it is perhaps just as well that it was a draw.
Such overseas visits are, of course, an important part of the jobs of the Tennō and other members of the Imperial family. While the Tennō is out of the country, his constitutional duties are performed by another member of the Imperial family — in this case, his younger brother and immediate heir. The need for such a person is probably the most critical reason for the recent change to the law on the Imperial family to secure the minimum necessary number of members over the next thirty years, by which time conservatives hope that Prince Hisahito will have got married and produced five (or so) adult sons.
What I want to talk about here, however, is the Shinto rituals associated with the state visits. These are standardised, and always reported on the front page of Jinja Shinpō. In this case, that was the May 25th, June 22nd, and July 13th issues.
The first article concerns a notification from Jinja Honchō to all jinja, asking them to perform a matsuri (a “chūsai”, which is more elaborate than most ceremonies) to ask the kami to protect Their Majesties on the day on which they leave, to recite a prayer for such protection during the daily offerings while they are gone, and to perform another chūsai matsuri to offer thanks when they return. Jinja Honchō also sends out suggested texts for the norito, which are fairly standardised. I do not know how many priests actually do this, but some certainly do.
The second is about the ceremonies that the Tennō performed before leaving. On the 12th of June, he attended the three sanctuaries in the Imperial Palace in person, dressed in the ceremonial vestments that he only wears to approach the kami (as far as I know), and entered each of the sanctuaries to announce that he was travelling abroad. He also sent emissaries to announce the journey at both the Inner and Outer Sanctuaries of Isë Jingū, and at the tombs of Jinmu Tennō (the first Tennō), and those of Shōwa Tennō and his Empress, Kōjun (this is the most recent Tennō who is dead, so the emissaries go to both ends of the line of Tennō).
The final article is about the ceremonies on his return. On the 29th of June, the Tennō again went to the three sanctuaries in the Imperial Palace to announce his safe return, and a few days later sent emissaries with the same news to Isë and the three tombs.
These events are standard, and are always front page news for Jinja Shinpō, but not anywhere else, so I am sure very few Japanese know that they happen. They are not state ceremonies, because they are religious, but neither are they purely personal. The Tennō is doing this as the Tennō.
Incidentally, the Empress was not directly involved. Reports of the Shinto rituals at the court very rarely mention her, but that is not a feature of the ceremonies per se. The previous Empress, as far as I recall, normally attended, paying her respects after the Tennō. The Crown Prince’s consort also almost invariably attends when he plays a part in one of these ceremonies (he didn’t this time), and Jinja Shinpō describes her as paying her respects “同列” (dōretsu), which means either “in the same line”, or “on the same rank”, and I think that means that they do it at the same time. I do not know the reasons for these differences, so I am not going to speculate.
One custom about which I will speculate is that when death-anniversary ceremonies for historical Tennō are held, there is a ceremony at the sanctuaries in the Imperial Palace in Tokyo, attended by most of the Imperial family, and one at the Tennō’s tomb, generally in Kyoto, attended by Princess Akiko. I have no evidence beyond this, but I know that Princess Akiko lives in Kyoto and most Imperial family members live in Tokyo, so I am willing to speculate that the reason for this particular custom is entirely practical.