"Joko" is honorary title of the emperor who retired after giving up the throne. When Joko becomes a Buddhist, he changes from Joko to the honorary title "Ho-o".
"Joko" reminds us of the era of "Insei", but it continues as an institution from the 7th century to the present.
On May 1, 2019, the emperor Kinjo will become Joko, so it will be familiar to us.
Dajo-Emperor (Joko) became necessary as Emperor retired and gave way to the next person
When the Emperor retires and gives up the throne, that person can not affix "Emperor". So it came out "Dajo-Emperor (Joko)" is the honorary title.
Dajo (太上) has the meaning of "the best person, the supreme best." Dajo-Emperor (太上-天皇) is generally called shortened "Joko (上皇)".
The Emperor is the highest ranked in Japan. Since that person experienced the emperor and gave way up, it will be "Joko" going further on.
So far Joko was located higher than the Emperor. However, Joko in the future seems to be in a position to watch the emperor. To the last, the emperor is the highest form.
Joko starts from the empress (Joko Jito)
The term "Emperor(天皇)" and "Joko(上皇)" was institutionalized by Taiho-Ritsu-Ryo which was enacted in the year 702 AD.
It is like a constitution composed of Ritsu (律. Criminal law) and Ryo (令. Civil law, Administrative Law).
At the time of the 7th century, it was transmitted from China, one of the developed countries of the world.
Japan began to introduce it to join the developed countries of the world.
The first Joko in Japanese history is the 41st Empress Jito.
It is surprising that the first Joko in the successive emperor is a woman, because the Japanese recalls with "Joko" because the empress does not appear "Insei". However, it was also the 35th Empress Kogyoku who first retired the Emperor.
Emperor's abdication history is old
Empress Kogyoku for the first time to abdicate in the emperor's succession is "Isshi-no-hen (乙巳の変)", whose son, Prince Nakano-oeno, killed SOGANO, Iruka in front of the Emperor. (645 AD)
Because the Prince Nakano - oeno was also Crown Prince, the Emperor Kogyoku took responsibility for the turbulence and abdicated the Emperor.
This abdication was not an ordinary system, it was an unexpected event.
As it is in such a state, no system has been established for abdication. Of course, there is no system called Dajo-Emperor. People of those days used the title "Sumemioyano-mikoto(皇祖母尊)". "Great Mother of the Emperor" would be like that.
The first Joko in successive Emperor is Empress Jito, but the de facto first Joko will be Empress Kogyoku. However, it is an accident.
Empress Jito is the emperor who abdicated second. Empress Jito is the grandson of Empress Kogyoku and is the daughter of Prince Nakano-oeno.
In the era of Jito Emperor, the legal system named Asuka-kiyomihara-Ryo has been developed, and Taiho-Ritsu-Ryo which developed it was near completion. In this Taiho-Ritsu-Ryo "Sumemioyano-mikoto" will be institutionalized as "Dajo-Emperor".
In this way, the first Joko becomes Joko Jito.
What is "Dajo-Ho-o (Ho-o)"?
"Dajo-Ho-o (太上法皇)" is the honorary title of Joko who became a Buddhist. In general it is abbreviated as "Ho-o (法皇)". The Pope will be close.
The Emperor is a ritual king who performs rituals of Japanese ancient religion (Shinto). And it is representative of Shinto. As the position of the king of religious rituals, the Emperor could not have become a Buddhist during his reign.
On the other hand, Joko comes out who becomes Ho-o as a Buddhist. Joko 's position was more free than the Emperor.
The first Ho-o is Emperor Uda of the Heian period
In the emperors of the past, the first Ho-o became the 59th Emperor Uda of the Heian era.
Emperor Uda is a rare emperor who experienced a position other than the royal family. Because he was such a person, he would have done something new.
For now, the 112th Emperor Reigen of the Edo era has become the last Ho-o.
On May 1, 2019 Emperor Kinjo will be Joko. If Joko becomes a Buddhist, Ho-o may be born for the first time in about 280 years.
Why call it "blah blah blah-In"?
We call the residences of Joko and Ho-o "In (院)".
From there we will call Joko "blah blah blah-In". blah blah blah is the emperor, Joko's posthumous name, it is the name of the area of the house.
When calling royal names, you may use places that live instead of their names. For example, we call the crown prince "Togu (東宮)".
Togu is the residence of the crown prince.