TOKYO — Six months ago, Naruhito, the new emperor of Japan, received a sword, a jewel and official seals in a sacred ceremony that heralded his succession to the throne after his father, Akihito, became the first emperor to abdicate in more than 200 years.

It turns out that was only a prelude.

On Tuesday, Naruhito, 59, took part in another enthronement ceremony — one in which he formally declared his ascension to the world’s oldest monarchy — and this time he actually got to sit on a really big throne.

Also this time: The empress, Masako, Naruhito’s wife of 26 years, was in the room. In May, Masako, 55, was not allowed to attend the ascension ceremony, in part because Imperial Household law prohibits women from succeeding to the throne.

Why the long gap between ceremonies? A new emperor usually takes the throne after his predecessor dies. A short ceremony is quickly arranged, and a bigger event — the one held Tuesday — follows some time later. (When Naruhito’s father, Akihito, took the throne, he waited a full year after the death of his father, Hirohito, the wartime emperor.)