Princess Aiko was spotted enthusiastically penning down notes at a Sumo match, a public event called "tenran" in Japan. In these events, members of the royal family typically make appearances. Aiko's enthusiasm and diligent note-taking serve to highlight her interest in the traditional sport and its cultural significance.

Sumo is highly respected in Japan, being a centuries-old sport with traditional and cultural connotations. The interest of a member of the royal family like Princess Aiko highlights the sport's prestige and importance in Japanese society. The younger generation's interest in these traditions helps to maintain Japan's unique cultural heritage.

In comparison to the US or EU, public appearances by Royal Family members during sports events are less common. It would be akin to a member of the British Royal Family being spotted enthusiastically studying a cricket match or a president attending a baseball game, reflecting their personal investment and the cultural significance of the sport.