Japan's Princess Kiko and her newborn son left a Tokyo hospital Friday, a week after the birth of the first new male heir to the Chrysanthemum Throne in four decades.

Hisahito's birth was hailed as forestalling a succession crisis for one of the world's oldest imperial systems, which allows only male rulers.

CountryWatch: Japan

Footage aired by national broadcaster NHK showed Kiko walking out of the hospital with the baby in her arms, accompanied by her husband Prince Akishino. The prince is the second son of Emperor Akihito.

Emperor Akihito's two sons had three daughters between them but no sons until the new arrival.