The information below has been provided by Dr. Masato Tojo’s responses to the Distinguished Jamshid Jamshidi’s inquiries regarding the ancient Japanese calndar.
1. Chinese calendar
The traditional Chinese calendar is called Kyūreki旧暦 (old calendar) and/or Noureki農暦 (agricultural calendar). Its first day of a year was Winter Solstice in 1700 B. C. It was greatly improved in the time of the Tang dynasty under the influence of Persia and India. The new calendar is called Tai-en-reki大衍暦. This is the basic form of Kyūreki. Here are its characteristic points:
(a) Official first day of a year is Risshun立春 (315 Zodiacal degree). The reason why this day became the first day of a year is for the convenience of agriculture. This is the reason why it is called Noureki (Agricultural calendar).
(b) Astronomical first day of a year is Spring Equinox (0 Zodiacal degree).
(c) The center day of a month in Kyūreki (Tai-en-reki) approximately corresponds to the first day of Persian month (Table 1).
Note that Spring Equinox (b) and center day of the first month in Kyūreki (c) are developed under the influence of Persian and Indian astronomy and astrology.
(d) Spring Equinox (Shunbun) is the day when people venerate their ancestors. This tradition is said to be Iranian origin (Farvardin).
Table 1 Kyūreki (Tai-en-reki)
24 Solar Terms Nijūyon-sekki二十四節気
Beginning day 節（せつ）
Center day of Month 中（ちゅう）
Risshun立春 Zodiacal degree: 315 Gregorian day: Feb 4th
Usui雨水 330 Feb 19th
Keichitsu啓蟄 345 Mar 6th
Shunbun春分 0 Spring Equinox Mar 21th
Seimei清明 15 Apr 5th
Koku-u穀雨 30 Apr 20th
Rikka立夏 45 May 6th
Shōman小満 60 May 21th
Bōshu芒種 75 Jun 6th
Geshi夏至 90 Summer Solstice Jun 21th
Shōsho小暑 105 Jul 7th
Taisho大暑 120 Jul 23th
Risshū立秋 135 Aug 7th
Shosho処暑 150 Aug 23th
Hakuro白露 165 Sep 8th
Shūbun秋分 180 Sep 23th
Kanro寒露 195 Oct 8th
Sōkō霜降 210 Oct 23th
Rittō立冬 225 Nov 7th
Shōsetsu小雪 240 Nov 22th
Daisetsu大雪 255 Dec 7th
Tōji冬至 270 Winter Solstice Dec 22th
Shōkan小寒 285 Jan 5th
Daikan大寒 300 Jan 20th
The time of the Tang唐（とう） dynasty (618-907) was a golden age of cosmopolitan culture.
Not only Confucianism儒教（じゅきょう） and Taoism道教（どうきょう）, but also Buddhism仏教（ぶっきょう）, Manichaeism明教（めいきょう）, Zoroastrianism祆教（けんきょう）, Nestrians景教（けいきょう） became officially recognized religions, and allowed to do every kind of religious activities freely.
The fact that two of the five Tang’s official religions are Persian indicates how great the influence and the presence of Persia were.
Actually there were many Persian high rank officials in Tang dynasty. An-roku-zan* was such a general who is well known in Chinese history.
An-roku-zan安禄山 (705-757): He was a general of Tang dynasty. He is a Sogdian born in Samarkand. Roku-zan禄山 (“lu-shan” in Chinese pronunciation) is transcription of his Persian original name “Roshn (light)“
2. Japanese Calendar
Tang’s calendar was imported to Japan and adopted in 737 and used until 1872. When the Meiji Restoration 明治維新（めいじいしん）started, the new government adopted Gregorian calendar in 1872 December 15th.
It was forbidden to use old Chinese calendar by the law. New Year’s Day (Nou-roz) was changed to 1st day of January according to the Gregorian calendar.
It is also forbidden to celebrate New Year’s Day according to the old calendar by the law. They set its start year on 660 B. C. which is the beginning day of Emperor Jimmu神武天皇’s reign (He is the legendary first emperor of Japan. He is Japanese Jamshid).
This calendar system is called Kōki皇紀. Gregorian 2010 is Kōki 2670. The first day of a financial year became April 1st in 1877 by adopting English financial year. Ideally it should be Spring Equinox, for the convenience of Gregorian calendar it became April 1st. Spring Equinox (Shunbun), which is the day when people venerate their ancestors and pray for the harvest in the Shintō shrines, became the day of veneration of Emperor’s ansectors and pray for the harvest in 1878.
In early Meiji era, all the junior high schools, high schools, universities began on September according to Western tradition. But they changed its beginning day to April 8th (its financial year begins on April 1st). Thus government offices, agencies, schools and companies begin their year on April 1st (spiritually on Spring Equinox).
After the World War II, the Gregorian calendar became the sole official calendar in Japan. The Kōki calendar was forbidden to use in public by the law. If one print to sell Kōki calendar, he will be punished by the law. The financial year and the other traditions remain untouched except one thing. It is Shunki-Kōreisai春季皇霊祭.
Before the World War II, Spring Equinox Day is an official national holiday and called Shunki-Kōreisai. But after the World War II, it was forced to change its name to Shunbun-no-hi春分の日 by GHQ, and became a day to spend visiting family graves and holding family reunions.
Still Spring Equinox Day and April 1st are important days for official and financial activities in modern Japan. Note Among Japanese Shinto-occult groups and right-wing activists and ideologues, the Kōki calendar is still used today.
3. The Starting Year of Calendar
In my opinion, the starting year of calendar should be the spiritual starting point of the people and their culture.
Point 1 For Iranians and the world, their culture before hijrat is too precious to disregard.
Even after Islamization, Iranian culture is still living and giving great influence upon it.
Point 2 In a long term view, Mohammedan culture is just a part of Iranian culture.
Therefore people of Iran, whether he/she is Mohammedan, Simorghian or others, should seek their spiritual starting year in the ancient Iran which will release Iranian vast potentials. It seems to me Shah Jamshid the father of civilization is much attractive choice. これからも、どうぞよろしくお願いいたします。
BEHROOZ o PIROOZ bashid. 敬具 東條真人
Dr. Masato Tojo