It is recorded that: This day being the Tencho, a great drinking feast was held for all the ministers, fine sake that are favoured [by the Emperor] were presented.

[3] Tenchōsetsu paralleled Chikyūsetsu (地久節), "Chikyū Festival", which referred to the Empress consort's birthday.

[3] The two names originate from the idiom in Chinese: 天長地久, borrowed from Lao Tzu's Tao Te Ching during the reign of Emperor Kōnin (708–782 CE), meaning "The sky and the earth, the universe is eternal," and expressed a hope for the eternal longevity of the reigning Emperor.

After World War II in 1948, the government renamed it to Tennō tanjōbi (天皇誕生日)-- the literal translation of emperor's birthday--and made the day a public holiday.

[8][12][13] However, the emperor addressed and thanked the public for their wishes in a press conference[14] and a recorded video message[15] 2020 and 2021 respectively.

Many citizens write letters to the Emperor during the week leading up to his birthday, and display the Japanese flag on the day.

[16] The emperor, accompanied by the empress, and several other members of the imperial family appear on a palace balcony to acknowledge the birthday greetings of well-wishers waving Japanese flags.

Only on this occasion, and during New Year's celebrations on 2 January, are members of the public permitted to enter the inner grounds of the palace.

[16][3] On the day of the holiday, the Imperial Palace complex and the surrounding streets are guarded by police, which, according to tradition, hand out small flags of Japan at the gate for free.

[3] Once his thanks and public greetings are concluded, the crowd begins to wave flags and the Imperial Family retreats inside the palace.

[16] The same evening, national television broadcasts a special during which the emperor addresses a few words of thanks to the country.