The younger brother line and the Office of the Crown Prince: invitation sender designation and the approval chain

On September 10, 2025, the Akishino household hosted a luncheon connected to Prince Hisahito’s coming-of-age events. Based on reporting, rumors circulated about the resignation of the Grand Master of the Office of the Crown Prince. Four issues warrant review: the approval chain, jurisdiction over sender designation, the decision maker for the name, and the approval flow.

The “younger brother line” refers to the imperial branch descended from the Emperor’s younger-brother line. The Heir Presumptive (Kōshi) is first in the line of succession, while the Heir Apparent (Kōtaishi) is treated as the next Emperor.

Definition and scope of the younger brother line

The Heir Presumptive is first in the line of succession. In the order of appointment as Regent, Article 19 of the Imperial House Law prioritizes the Heir Apparent. Provisions on loss of imperial status differ under Article 11 of the Imperial House Law. As to certainty of status, the Heir Apparent is fixed as the next Emperor, while the Heir Presumptive remains only the current first in line.

These legal distinctions can plausibly lead to variations in approval-chain design, jurisdictional boundaries, and accountability. A plausible mechanism is that the approval chain can be influenced from two directions: the Office of the Crown Prince and the wishes of the imperial family member. This could, in theory, produce duplicative sign-off sequences or perceived conflicts over who determines the sender designation.

During the February 26 Incident, a contested rumor in some postwar accounts portrayed Prince Chichibu as a hidden instigator—an ultranationalist young officers’ attempted coup in Tokyo in 1936—illustrating how peripheral narratives can proliferate during emergencies.

Command structure of the Office of the Crown Prince and sender designation

Authorized headcount: 51 (FY2025 revision). Officials: 10 (Kyūmukan within the Office of the Crown Prince) (Source: Cabinet Order on Authorized Numbers of Personnel of Administrative Organs, Reiwa 7 revision). Public relations expenses: JPY 53 million (FY2025 budget request; approx. USD 0.35 million), agency-wide and not specific to the Office of the Crown Prince (Source: Imperial Household Agency, “FY Reiwa 7 Budget Request”). Goyōgakari are part-time advisors.

The Grand Master of the Office of the Crown Prince is the Office head. The Imperial Household Agency’s official position is: “there is no fixed rule for names; the Office of the Crown Prince decides based on the event’s content.”

Reporting summarizes the sequence as follows: drafting under the Grand Master’s name, expression of preferences by Their Highnesses, change to a Goyōgakari, and dispatch of invitations. Crown Prince Akishino (Fumihito) and Crown Princess Kiko expressed their wishes, and the Office changed the sender designation to that of a Goyōgakari; invitations were then sent.

When a resignation rumor is in play, the relationship between jurisdiction and practice is subject to reexamination. Gaps in peacetime may surface as approval delays.

International comparison: logics of reduction

In Denmark, the Queen was the decision maker; effects included rationalizing titles for Prince Joachim’s children and reducing public funding. Prince Joachim’s family said they “respect the decision” and adopted a “future-proof the Royal House” framing.

In Sweden, the King was the decision maker; the children of Prince Carl Philip and Princess Madeleine were delisted from the Royal House, were no longer styled HRH, and were excluded from public funding. The families indicated they would continue activities.

In the United Kingdom, Buckingham Palace and the Monarch agreed: the Duke and Duchess of Sussex left as working members, did not change titles (no public use of the HRH style), and the relationship among public funding, public duties, and public offices was redefined, while the “half-in, half-out” proposal was rejected.

A contextual reading is: Japan is moving toward system strengthening, while Denmark and Sweden pursue family downsizing, and the United Kingdom is redefining working members.