Japan's new imperial baby - the first male born in 41 years - has been named Hisahito during a traditional ceremony in hospital in the capital, Tokyo.
Prince Akishino chose the baby's name in a traditional rite
The baby was born to the emperor's second son Prince Akishino and his wife Princess Kiko, on 6 September.
Prince Hisahito is third in line to the Chrysanthemum throne, behind Crown Prince Naruhito and his own father.
His birth, which headed off a crisis in the imperial succession, has been widely celebrated in Japan.
The name Hisahito is composed of two characters. The first means serene or long-lasting.
The second, which means virtuous, has traditionally been included in the name of royal males.
A palace spokeswoman, Yuka Shiina, said that name was chosen in the hope that the baby had a long prosperous life with even-tempered peace of mind, the Associated Press news agency reported.
The prince was named in a private ceremony at the Tokyo hospital where Princess Kiko gave birth.
Currently only males can ascend the Japanese throne
Emperor Akihito has two sons, Naruhito and Akishino
If Naruhito died without a male heir, Akishino succeeds
His baby son, Hisahito, is third in line
Any children born to Princess Sayako cannot ascend because succession follows male line
According to tradition, his father chose the name by writing it on a piece of paper and placing it in a wooden box by his son's pillow.
His mother selected a personal crest, resembling an umbrella pine tree, that will be used to used to mark his belongings.
The crest was chosen in the hope that the baby will grow straight and tall, the palace said.
The baby boy, who has not yet been seen in public, is the first male born into the imperial family for over four decades.
Prince Akishino and Princess Kiko have two daughters, while Crown Prince Naruhito and his wife, Princess Masako, have a young daughter.
Current Japanese law forbids women from ascending the throne.
Prime Minister Junichiro Koizumi had been advocating constitutional reform to change this, but the debate, although supported by the public, was shelved when news of Princess Kiko's pregnancy was announced.
Mr Koizumi's likely successor, conservative lawmaker Shinzo Abe, appears lukewarm on the issue, even though a poll on Monday by public broadcaster NHK showed that 56% of respondents backed the legal changes.
Mother and baby are expected to leave hospital in a few days.