How True North Was Measured
by the Pole star in Ancient China

How True North Was Measured
by the Pole star in Ancient China
Meridian
Ideal Appointed star(Same right ascension)

Leading
star

α

Pole
Star

Pole
θ
θ：Difference
from meridian

Next
Leading
starThis error (θ) was left in
the ruin of capital castle.

竹迫 忍
TAKESAKO Shinobu
http://www.kotenmon.com
takesako@mrj.biglobe.ne.jp
December 24, 2022 , 1st ver.

How True North Was Measured
by the Pole star in Ancient China
１． The discovery of the True north measurement method by the Pole Star
２． Identification of the ancient Pole Star for the True north measurement
３． Principle of True north measurement by Pole Star
４． True north measurement instruments and methods
５． Verification of the remains of ancient ruins in China
６． Verification of the orientation of ancient remains in Japan
７． Example of the dating by the orientation of excavated remains
８． Dating of the ancient straight road by its direction
９． The introduction of Hokushin ruling thought to Japan
１０． Summary

4
12
20
29
36
66
71
78
88

・ Maps used in presentation are from Google Earth Pro.
・ The author has used Google Earth Pro to measure latitude and longitudeof ruins and calculate direction..

3©2022 S.Takesako

１． The discovery of the True north measurement
method by the Pole Star.

4©2022 S.Takesako

Thoughts behind Kyoto's beautiful streetscape
Kyoto's north-south streetscape is based on Jobo（Block） in the Heian period.
Tatsuhiko Seo's "Changan City
Plan"(2001)p.158 says，"the ancient
capital of China, was built as a stage
for dynastic ceremonies and embodies
the existence of a heavenly mandate.
By doing so, the emperors on earth
tried to prove their legitimacy."➢ The True north measuring method
for the stage of the dynasty ritualthat embodied the Hokushin (Godof pole) ruling thought was the True
north measuring method using thePole Star.
➢ This idea and the style of palacepalaces were introduced to Japan in
the Asuka(7c) period and carriedover to Heian period.

Kyoto,JapanNorth

Built inEdo Period(degeneration)

5©2022 S.Takesako

The construction process of Chang'an Castle① Palace

Palace太極殿 was built in
the center of the palace

Palace
8.6km

Imperial
PalaceKudaranoMiya
NaniwanoMiya
NochinoAsukaokamotonoMiya

Asukaitabukinomiya
Central Axis
(meridian)

Outerskirts④ Outskirts wall

PalaceImperial
PalacePalace③ Street
Walls for section

After
FujiwaraKyou

9.7km
6

1.5km

Imperial
Palace8.6km②Imperial palace/main 6 streets

It is believed that this knowledge was brought
to Japan by students for Sui returned in 632.

Tatsuhiko Seo's "Changan
City Plan"(2001)p.121©2022 S.Takesako

Reconstruction drawing of Chang'an Castle.

【「中国都城歴史図録 第二集」(1986)p.148-149より】
7©2022 S.Takesako

How did they put the central axis of the capital on the meridian?
⚫ 妹尾達彦著『長安の都市計画』(2001)p.118(Tatsuhiko Seo's "Changan City Plan")
The direction is measured by Pole star
➢ the True north measurement method using the sun
and the Pole Star called "取正之制" (zhèngzhīzhì) in 『営造法式』（1103, Yíngzào fàshì） But
timing of the measurement is not mentioned.
➢ the direction of Chang'an Castle was 16 minutes
west from true north. (1 degree is 60 minutes.)① Check the mridian by sun⚫ 北条芳隆著「古墳の方位と太陽」 (2017)p.86，(Yoshitaka Hojyo's "Directio of ancient tomb and sun")➢ and if he pays attention to the time of the Pole
Star, he should have been able to increase the
16 min.
accuracy to around ±0.1°.
HR4893
Pole
Star

8

The problem : How they know
the time when the Pole Star wasnear the meridian without clock?

Pole

1.4°
(AD582)Meridian②In the night, measure
the direction by Pole star.
"取正之制" in "営造法式"『石印宋李明仲営造法式』
東北大学附属図書館蔵©2022 S.Takesako

Documents that can assume the time of the measurement『詩(経)』(Shijing)『晏子春秋』(Yanzi Chunqiu)『詩(経)。定之方中(，作于楚宮)。又揆之以日(，作于楚室)。
注云。定，營室也。方中，昏正四方也。揆，度也。度日出日入，以知東西。南視定，北準
極（星），以正南北。』 (from『営造法式』)『古之立国者，南望南斗，北戴樞星，彼安有朝夕哉』

Translation：According to the Book of Poetry, when9

the fixed star is in the middle of the south (the temple isbuilt on the hills of Chu). Measure the shadow of the sunand determine the direction (build a palace on the hill of
Chu). According to the notes ("毛享傳"), the fixed (star) is
the Shi xiu("室"). Hochu(方中) is to set the four directions
correctly at dusk. Revolt(揆) is to measure. Measure thesunrise and sunset and know the direction of east and west.
Look at the southern fixed star and determine the northsouth direction correctly based on the north pole (star).
(This poem is related to the fact that Duke Huan(桓公) of
Qi(斉) helped Duke Wen(文公)of Wei(衛) to build a capital
castle in Chuqiu (楚丘,to the east of present-day Hui
County, Henan Province) in the first month of the 2nd yearof 僖公, year BC658.)(『営造法式』には記載なし)

Translation: One who establishes acountry in ancient times, observes
for Dou xiu(南斗) in the south,
receives a Pole star in the north, andsettles (corrects) the east and west.

There are descriptions of 28
leading stars which are notrelated to Pole star observations.

©2022 S.Takesako

Direction of Pole star at the Chunqiu era(Pole star : HR4927)
Direction from true north.(min. ,+:west)⚫ The direction from true north whenlooking at the Pole Star when theleading stars of Dou xiu and Shi are at
the meridian.
⚫ The direction is about ±20 minutes
from true north within Chunqiu era.
⚫ From the Chunqiu era at the latest, thePole Star was used to measure thedirection of capital castle.
HR is number of the Bright Star Catalog.
Pole(HR4927)
Year

True north whin Dou xiu
is at the meridian.
True north whin Shi xiu
is at the meridian.

RA.
α0

Confucius era

Dou xiuBC

Shi xiu

Dou xiu (φSgr,HR7039)

Shi xiu (αPeg,HR8781)

Dec.
δ0

RA.
α1

Dec.
δ1

α0－α1

Direc.
(min.)

RA.
α2

Dec.
δ2

α0－α2

Direc
(min.

-750

32.3

89.0

239.0 -24.4－206.7

－32.3

312.2

2.2

－279.9

－71.7

-700

44.4

89.2

239.8 -24.5－195.4

－14.8

312.8

2.4

－268.5

－56.2

-650

64.3

89.4

240.5 -24.7－176.2

2.9

313.5

2.6

－249.1

－41.0

-600

93.1

89.5

241.2 -24.8－148.2

20.9

314.1

2.8

－221.0

－26.0

-550

120.5

89.4

242.0 -24.9－121.5

39.0

314.7

3.0

－194.2

－11.2

-500

138.6

89.2

242.7 -25.1－104.1

57.3

315.3

3.2

－176.7

3.4

-450

149.6

89.0

243.5 -25.2

－93.9

75.9

315.9

3.4

－166.417.8

10©2022 S.Takesako

Azimuth line by Pole star(HR4893) with leading stars
and direction of the ruins of Capital castle

Direction from true north.(min. ,+:west)

The method of measuring directions using the Pole Star was
introduced to Japan in the Asuka period.
Gui xiu

Fujiwara-kyo

Shen xiu
Xu xiu(692)

Heian-kyo

Nagaoka-kyo

(

真
北
か
ら
の
方
位
分
，
正
は
西
偏
，
負
は
東
偏

)

11

Yamato 3 roads

Heijyou-kyo
year

Naniwanomiya
Naniwa-daido

Zhang xiu

Niu xiu

Ji xiuyear【at 2020/01/26】©2022 S.Takesako

２． Identification of the ancient Pole Star
for the True north measurement

12©2022 S.Takesako

The Pole Star from the Chunqiu era to the present
In ancient China, the Pole Star was not the imperial star,
but moved along with the movement of the celestial pole.

Ursa Minor
Pole star(HR424)
α UMi (present)
帝星(βUMi)

Imperial star

Pole star(HR4893)(隋/唐⇒宋/明) (550- 1600 )Pole star (HR4852)(後漢⇒晋⇒南北朝) (0 to 550)

Pole star (HR4927)(春秋⇒漢) (-800 to 0 )13Note: Star charts in the chart are stars up to 6.6 magnitude according to "SKY2000 Master Catalog,
Version 5" (2006).A star map in 300 AD. The numbers are the grades of light. The small yellow circle is©2022 S.Takesako
the position of the celestial pole. The declination scale interval is 2°.

Identification of Pole star (HR4893)
from Sui-Tang to Song-Yuan-Ming Dynast『其五，前世皆以極星爲天中，自祖暅以璣衡窺考天極不動處，乃在極星之末猶一度有餘。今銅儀天樞内徑一度有半，乃謬以衡端之度爲率。若璣衡端平，則極星常游天樞之外；璣衡小偏，則極星乍出乍入。令瓚舊法，天樞乃徑二度有半，蓋欲使極星游於樞中也。臣考驗極星更三月，而後知天中不動處遠極星乃
三度有餘(天樞徑)，則祖暅窺考猶爲未審。今當爲天樞徑七度(誤解)，使人目切南樞望之，星正循北極【。】樞裏周常見不隱，天體方正。』宋史天文志[彙編・第三冊] p.804

Distance from the pole (degree)⚫ Ling Zan (令瓚,early 700s) moved the Pole star in the viewing tube of thearmillary sphere and measured 2.5 degrees (radius 1.25 degrees) between thecelestial pole and the Pole star.
⚫ A government official (Song Dynasty: Shen Kuo 沈括) tested the Pole star for
three months, and found that the fixed point of the center of the sky was more than
3 degrees (wrong, diameter) from the Pole star. He found the radius to be about 1.5
degrees.
Distance from the pole (HR4893)
Moving the pole star in the viewing
tube of the armillary sphere。

令瓚(Ling Zan)

Pole

沈括(Shen Kuo)

Polse
star

Tube

14

Year

©2022 S.Takesako

Identification of the Pole Star(HR4852) from the Later
Han to the Northern and Southern Dynasties(6 c)『北極五星在紫微宮中，北辰最尊者也，其紐星爲天樞，天運無窮，三光迭耀，而極星不移，故曰「居其所而衆星共之」。樞星在天心，四方去極各九十一度。賈逵、張衡、蔡邕、王蕃、陸績皆以北極
紐星之樞，是不動處。在紐星末猶一度有餘。今清臺則去極四度半。』宋史天文志[彙編・第三冊]
p.820⚫ 賈逵(30-101)、張衡(78-139)、蔡邕(132-192)、王蕃(228-266)、陸績(188-219):
Everyone thought that the Pole star was the pivot of the heavens and did not move.
⚫ It was said that the pole star was still more than 1°from the place of immovable by the祖暅(Zǔ gèng) (person around 500).
⚫ Now (Song dynasty) when Qingdae清臺 measured it, it was 4.5 degrees.

Distance from the pole (degree)

Distance from the pole (HR4852)

清臺(Qingdae)

祖暅
Later Hun

15

Yera

©2022 S.Takesako

Identification of the Pole Star(HR4927) from
Chunqiu to Fomer Han Dynasties

Distance from the pole (degree)⚫ Confucius's Analects「北辰居其所而衆星共之」(The Hokushin is inplace and the other stars are with it.)。
⇒At the time of Confucius, it seemed immovable because it waswithin 1 degree from the Pole.
⚫ Lüshi Chunqiu in Qin 「極星與天倶游，而天極不移」(The Pole starmoves with the sky, the North Pole does not move)⇒It was about 2 degrees in the Qin Dynasty, so it appeared to move.
Sky at BC500 (scale is 2°in declination )Distance from the pole (HR4927)

Qin
HR4927

Confuciusyear
16©2022 S.Takesako

Why the Ancient Pole Star Wasn't Identified ?

Red stars like HR4852 andHR4927 were not listed in the
BOSS star catalog used byastronomers in the Showa period.。

α UMi(HR424)
北極星(現代)北極星(HR4893)(隋/唐⇒宋/明)

北極星(HR4927)(春秋⇒漢)
17

北極星(HR4852)(後漢⇒晋⇒南北朝)

Note : Sky at AD300.
©2022 S.Takesako

Movement of Pole star from Chunqiu to present
Chinese constellations based on the identification of the original map of the Jin dynasty(created in early Tang Dynasty).
Kitora勾陳(6星)帝星(βUMi)

Pole star(HR424)
α UMi (present)

北極(5星)
North Pole (5stars)

Imperial star

Pole star(HR4893)(隋/唐⇒宋/明) (550- 1600 )Takamatsuzuka

四輔 (4星)Pole star (HR4852)(後漢⇒晋⇒南北朝) (0 to 550)

Pole Star

Pole star (HR4927)(春秋⇒漢) (-800 to 0 )18

Note: Position at AD300年。 Kitora Astronomical Map is from 「キトラ古墳天文図 写真資料集」©2022 S.Takesako(2016) PL.5. Takamatsuuzuka star map is from 飛鳥歴史公園HP.

Angle of each Pole Star from the celestial pole

Angle from the Pole (degree)

Confucius' Hokushin was also the Pole Star.
Period when the true north measurement method was performed
in China using the Pole Star

Pole star (HR4927)(春秋⇒漢) (-800 to 0 )(HD113049)

北極星(HR424)(Present)(HD112028)(HD8890)

Pole star (HR4852)(後漢⇒晋⇒南北朝) (0 to 550)
(HD111112)

Confucius(北辰)

19Pole star(HR4893)(隋/唐⇒宋/明) (550- 1600 )In Japan, using the Pole staryear
©2022 S.Takesako

３． Principle of True north measurement by Pole Star

20

©2022 S.Takesako

Principle of True north measurement by Pole Star⚫

The celestial sphere revolves
around the earth's axis.
➢ The Pole star rotates as well.

⚫

The star south of the Pole Star of
the same right ascension and thestar 180 degrees away from thatstar are called appointed stars.
➢ The three stars are on thesame plane and rotate about
the earth's axis.
When the appointed star is at themeridian, the direction of the polestar is true north.
Stars 180° away is formeasurements in the opposite
season.

⚫

⚫

Earth's axis

Appointed
star
Pole star21©2022 S.Takesako

Example of simultaneous meridian passage of two stars(True north measurements in the Otsukyo period)

Big Dipper
4th star• During the Otsukyo period,
when the leading star of Zhen
xiu(軫宿) was in the south
meridian, the direction wasmeasured by looking at the
fourth star of the Big Dipper.
The resulting direction is 85
minutes west of north.
• If they are on the same lineof equatorial longitude, when
the south star is on themeridian, the north star is attrue northPosition at AD666
BigDipper(4th) HR4460 赤経：165.50 赤緯： 64.42
Zhen xiu(leadint) HR4662 赤経：167.11 赤緯：-10.15

22

Leading star of Zhen xiu©2022 S.Takesako

Examples of Pole star and Ideal Appointed Star
(Egypt, Khufu's Era)
⚫ The Pole star Thuban (αDra,
HR5291) and Antares (αSco,
HR6134) at the time the pyramids
were built have almost the sameright ascension.
⚫ At the estimated construction date
(2552 BC) of the Pyramid of Khufu(about 3 minutes westward fromtrue noth), Tuvan is about 1.4°
away from the celestial pole,⚫ The direction of Tuban when
Antares is mid-southern is 1.2
minutes east of true north, so it isalmost an ideal apointing star.
⚫ In order to obtain an direction close
to true north, it is important that thestar that measures the direction be23
close to the celestial pole.

Thuban(αDra)

North
Pole

Antares(α Sco)ObserverSouth Pole

赤経(BC
2552)
α

赤緯(BC
2552)
δ

光度
Mg

5291 11α Dra

185.3400

88.60913.65

6134 21α Sc o

184.6354- 6.4197

1.07

HR

星名
Name

©2022 S.Takesako

28 leading stars were used as Appointed stars⚫ In China, the twenty-eight
constellations of bright leading stars,
located near the equator and theecliptic, were used as reference
points for determining the positionsof the stars. If you measure thelongitude difference from theleading star, the precession iscancelled, and the relative position
hardly changes.
Average interval＝360°/28≒13°⚫ Since there is usually no bright starat the same right ascension as thePole Star, which is necessary for true
north measurements, the Chinese
used a nearby leading star instead of
an ideal Appointed star.

Potion of 28 leading star

黄道

天極

赤道

【Sky at AD1】

24©2022 S.Takesako

Estimate the error when using 28 leading stars
Meridian⚫ The maximum distance between
leading stars are 33°. Average is 13°.
Ideal Appointed star
⚫ If the Appointed star is properly
Leading(Same right ascension)
updated, the maximum value is 16.5°.
star
16.5°
⚫ If the Pole star is 1.5 degrees away
Maximum error can calculated as
16.5°
26min
Pole
θ＝ 1.5°x sin(16.5°) ＝26min.
αStar
If use the average, it is about 10 min.
1.5°

⚫ This error increases as the Pole Star
moves away from the celestial pole, so
the star closest to the celestial pole wasimportant and called the Pole Star.
⚫ it was natural to measure the true northwith Hokushin, which is ruler in thesky.
⚫ As a result of verification, the optimalleading star is not always selected.
25

North
Pole

θ
θ：Difference
from meridian

Next
Leading
Star

This error (θ) was left in
the ruin of capital castle.
Observer©2022 S.Takesako

Calculation example of true north measurementwith leading stars⚫ Chang'an Castle was built on 582 AD. Pole
Star(HR4893) is 1.4° away from the pole.
⚫ Since the Pole Star's right ascension is 334°,
the Appointed star is Shi xiu or Yi xiu, which is
180° away. . In this example, since Shi xiu ison the meridian during the daytime, Yi xiu willbe the Appointed star.
⚫ Without knowing the time when the Pole Star isnear the meridian, if you measure the direction
at 10p.m., it will be 97 min. west of true north.
⚫ If you measure the direction of Pole star at 3
o'clock in the morning when the winged star ison the meridian, you will get the direction of
11.5 minutes to the west of true north.
⚫ Matches the direction of the remains of the Sui
Daxing Castle (582) within a few minutes oferror.。
26

Time Pole star(HR4893)
αδ

Leading stars
Xiu
α

Az
(min.)

室宿Shi xiu
180°

22:00

3:00
Yi xiu翼宿Time when the leading star on meridian©2022 S.Takesako

The point of the Direction measurementin the map of Tang Chang'an Castle

14.9min. westward

12.6 min. westward

The directions of these walls
are close to the calculated 11.5
minutes westward of true north.

5.7min. eastward【「中国都城歴史図録 第二集」(1986)p.148-149より】
27

Note: The direction measurement is based on latest image of Google Earth (2021/07/30 version)©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4893) and leading starand direction of the remains ancient castle

Chang'an
西暦年代【翼宿】
Yi xiu28

Direction on the page 27.

Xi'an
【角宿】
Jiao xiu【Location：34.29°(Chang'an)】 ©2022 S.Takesako

４． True north measurement instruments and methods

29©2022 S.Takesako

True north measuring instrument
solar compass⚫ 『営造法式』 "Yíngzào fàshì" was compiled by
Li Yi (李誡)during the reign of Tiezong of theSong Dynasty. There is an explanation of thetrue north measurement method using the sun
and the Pole Star.

13cm⚫ Measurement uses solar compass andObservation tube without a lens.
⚫ The sun compass is a disc with a diameter ofabout 43 cm and a gnomon about 13 cm high
(3 mm in diameter) is placed in the center.
⚫ Observation tube is 57cm long and 9.5cm
wide. Viewing holes with a diameter of 16
mm are drilled in the front and rear plates of it.
The field of viewing hole is about 1.6 degrees
in angle . The height of Observation tube is
95 cm above the ground, and the line-of-sightdistance on flat ground is about 3.5 km. A long
distance is also possible if you set up
30
scaffolding.

43cm

Observation tube
9.5cm

95cm

57cm

field view
= ± 48min.
Base『石印宋李明仲営造法式』
東北大学附属図書館蔵©2022 S.Takesako

Similar Observation Instruments Exist in Ancient Times① Han Dynasty sun compass(excavated)② Observation tube

⚫ Although it is explained as asundial in various places, it isactually a compass of the sun.

⚫ 『淮南子』(Former Han)
「人欲知高下而不能,教之用管準則説」(If someone does not know the height ofthe object, please instruct them to use atube and water level.)

True North管(Tube)Sunrise ofsummersolstice

31

Sunsetofsummersolstice

Leveling with a water level(準)©2022 S.Takesako

Work at daytime: Installation of the telescopelike device on the temporary meridian
The purpose is to limit the range to search for the faint PoleStar to the vicinity of the meridian.
①If there is no bell to signal the Noon

②If there is bell to signal the Noon

⚫ The point where the shadow of the ⚫ place the tube on the meridian bystick is the shortest is the mid-southpassing sunlight at noon. Ancient timeof the sun, which is the north-south
is true solar time, so at noon the sun isline (meridian).
due south.
Meridian

Meridian(at noon)

Observation tube

32

Installation accuracy：±few deg.
Meridian

Installation accuracy:±1degree(Depend oh the clock)©2022 S.Takesako

Work at nighttime①： Introducing Pole Star
To reduce the installation
error of the observation tube.

Pole
Star

Time Pole star(HR4893)
αδ

Leading stars
Xiu
α

Az
(min.)

Pre-setting of pole stars⚫ Before observing the Appointed starin the south, capture the Pole Starand and introduced into the center ofthe observation tube. (Fine-adjust
the pedestal ) ⇒The installation
error is within about ±30 arc
minutes. Yi xiu at meridian: 3:00

observation tube
The effect of this error
on the measured
azimuth angle iswithin 1 arc minute.

Zhang xiu at meridian: 2:00
Difference is about 30 arc min.
Setting error:±30 arc minutes.

33©2022 S.Takesako

Work a nighttime②： Measure the direction after
observing the Appointed star at meridian
The method with Appointed star enables accurate survey in one day.
①Observe Appointed star at meridian⚫ Point the viewing tube to the south andobserve the zenith of Appointed star.
Wait for the fixed star to come to thecenter of the telescope.

②Observing the pole star to determine
the direction of the north⚫ When the Appointed star comes on themeridian, reverse the viewing tube andintroduce the pole star into the center of
the tube. (Fine tune the pedestal ofviewing tube)
Pole star

Appointed Star

Appointed Star

Viewing Tube
Viewing Tube

34

Temporary
MeridianFine-tune thedirection of
the pedestal,
Determine theconstruction
direction.

Temporary
Meridian©2022 S.Takesako

How to select the best Appointed star
② the leading star closest to the meridian① Find true northby orbiting the pole star in the tube,
the viewing tube is turned to true north.

Pole Star

When Pole star is in thecenter of the cylinder
facing due north, theleading star closest to
the meridian is taken as
the Appointed star.

Leading starerror

North Pole

Viewing Tube
True North（Meridian）
It takes months to determine the true north.

Viewing Tube

Mridian35

Not mentioned in 『営造法式』©2022 S.Takesako

５．

Verification of the remains ofancient ruins in China.

36©2022 S.Takesako

Location of Ancient Chinese Cities

北魏
平城(大同)
Pingcheng(Datong)

北京
Beijing

ちょう かんたん

趙・邯鄲Handan of Zhao
長安
Chang'an
37

洛陽
Luoyang

500km©2022 S.Takesako

Positional relationship of ruins around Chang'an
漢代
祭祀坑・五方基壇
Ritual pit and 5 altars

38

漢・皇帝陵

渭水

Hun Imperial Tombs

秦・咸陽城
Qin's Xianyang castle

始皇帝陵
Mausoleum of theFirst Emperor

漢・長安城

75ｋｍ

Han's Chang'an castle

明・西安城

秦・阿房宮
Qin's Afang Palace

Ming's Xian castle

隋・大興城 Sui's Daxing castle
唐・長安城 Tang's Chang'an castle

子午谷
Meridian valley©2022 S.Takesako

Ruins from Chunqiu era to the Former Han Dynasty：Pole Star(HR4927)
Chinese constellations based on the identification of the original map of the Jin dynasty(created in early Tang Dynasty).
Kitora勾陳(6星)
Pole star(HR424)
α UMi (present)

北極(5星)
North Pole (5stars)
Pole star(HR4893)(隋/唐⇒宋/明) (550- 1600 )Takamatsuzuka

四輔 (4星)Pole star (HR4852)(後漢⇒晋⇒南北朝) (0 to 550)

Pole Star

Pole star (HR4927)(春秋⇒漢) (-800 to 0 )39

Note: Position at AD300©2022 S.Takesako

Orientation of Zhao royal castle(oldest verified remains)
The capital of Zhao was moved to Handan in 386 BC during the Warring States
period. Even now, the remains of the four north and south castle walls of theroyal castle remain.
38.9min. eastward

29.5min.
eastward

North
castleWestcastleEastcastle30.2min.
westward

37.6min.
eastward
2.2km

40©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4927) and direction of
the remains of Zhao royal castle

41【12室宿】
Shi xiu
West wall of west castle

Year
East wall of west castle
East wall of east castle
West wall of north castle【26翼宿】Yi xiu【Longitude：36.57°(Zhao royal castle )】©2022 S.Takesako

Direction of Qin Shi Huang Mausoleum
The location of the base of the mound isunclear. Masahiro Etaya et al. (2014) measured
the boundary stones of the outer castle , thedirection of the central axis is average of 1.4
degrees (84 minutes) east of true north.

1.4degree eastof true north(average)(1.5°east)(1.3°east)

Construction of the mausoleum began when hewas 13 years old when he ascended the throne
as a royal tomb of Qin. Furthermore, it isbelieved that it was expanded as an imperialmausoleum with the unification of China (221BC).
Assuming that the survey after the enlargement
are made around the time of national
unification (221 BC), using Pole star HR4927
and leading star of Yi xiu , the direction is 84.7
minutes east of true north, which is almost thesame as the measured average.

1.0km

42

©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4927) and direction of
the Qin Shi Huang Mausoleum【12室宿】
Shi xiuyear【26翼宿】Yi xiuEast of outer castle
West of outer castle

43【Latitude：34.29°(Chang'an)】 ©2022 S.Takesako

Direction of Former Han Dynasty Chang'an Castle⚫
⚫

Chang'an Castle ：Construction began in 202 BC
Castle wall：Construction began t in 195 BC

5 altars
Ritual pit➢➢➢

Ms. Huang(黄暁芬(2006) ) envisioned a 75 km central
axis line and measured and verified it with GPS.
Measurements of direction inside the castle by Mr. Uno
4th Emperor's Mausoleum(Yangling):19.2minutes west

Han Dynasty
Chang'an Castle

46.9min. east
Changling

Chang'an Castle(0.6 degree west)(0.5 degree east)

Han Dynasty
Chang'an Castle

Gate of An

56.2 sec. east
(from valley)(0.3 degree east)

6.4km

41.5min. east
(from the west hill)
Meridian valley

44

Gate of An©2022 S.Takesako

Positional relationship of ruins around Chang'an Castle
祭祀坑と五方基壇
Ritual pit and 5 altars

46.9min. east

75ｋｍ
Hun's Chang'an Castle

41.5min. east
(from east hill)
Meridian valley45©2022 S.Takesako

5 altars, Changling and Meridian Valley
Ritual pit and the 5 altars

Meridian Valley(子午谷)

5方基壇 5 altars
祭祀坑
Ritual pit

46.9min. eastward
from Chang'an Castle
570m

568m

Changling (長陵)Empress
Lu's Tomb

46

Westernhill side
41.5 min eastward

Ms. Huangmeasurement
56.2sec eastward(about 1min.)Liu Bang
Tomb©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4927) and direction of
the ruins around Chang'an Castle

47【13 Bi xiu 壁宿】
Chang'an Castle (an gate axis)【14 Kui xiu 奎宿】
Yangling
Chang'an castle to center of Changling【 0 Jiao xiu 角宿】
year【 15 Lou xiu 婁宿】
Within 5 altars
Chang'an Castle (east gates)
Meridian valley to Chang'an castle
Chang'an castle to 5 altars【27 Zhen xiu 軫宿】【Latitude：34.29°(Chang'an)】©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4927)
and direction of the ruins

48[Shijing]a palace was built
on the hill of Chu.
(BC658)【斗宿】
Dou xiu

春秋
Chunqiu

毛亨(Mao Heng)【室宿】
Shi xiu

戦国
Warring States

秦
Qin

漢
Hun

Worst
Direction

It fits Dou xiu in Yanzi Chunqiu.
It is thought that the Appointed star of Shijing is Shi
xiu because Mao Heng, who made the annotation,
was a scholar from the end of Qin to the beginningof Han, when Shi xiu was the Appointed star.
©2022 S.Takesako

Ruins from the Later Han to the Northern and Southern
Dynasties ：Pole Star(HR4927)
Chinese constellations based on the identification of the original map of the Jin dynasty(created in early Tang Dynasty).
Kitora勾陳(6星)
Pole star(HR424)
α UMi (present)

北極(5星)
North Pole (5stars)
Pole star(HR4893)(隋/唐⇒宋/明) (550- 1600 )Takamatsuzuka

四輔 (4星)Pole star (HR4852)(後漢⇒晋⇒南北朝) (0 to 550)

Pole Star

Pole star (HR4927)(春秋⇒漢) (-800 to 0 )49

Note: Position at AD300©2022 S.Takesako

Northern Wei, Pingcheng (Ming, Datong Castle)⚫ Datong Castle, located in thenorthern part of Shanxi Province,
was called Datong Prefecture in
the Ming Dynasty.
⚫ The walls that still remain today
were built from the fifth year of
Hongwu (1372) on the basis ofancient walls (Northern Wei,
Tang dynasty), starting with theouter wall of Pingcheng, thecapital of the Northern Wei
Dynasty.
➢ In 398, Emperor of Northern
Wei established Heicheng as thecapital, and in 406 he built asquare outer wall south of castle.
➢ The direction is 6.5 minutes
50
westward on average.

13.4min. westward

0.5min. eastward

1.8km©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4852)
and direction of the ruins

51

Average value of wall direction
亢宿
Kang
xiu

【Latitude：40.09°(Datong)】©2022 S.Takesako

Northern Wei Luoyang Capital castle⚫ Moved the capital to
Luoyang in 493, and built
a round hill in 501.
➢ The direction from castle
to round hill 19.2min east.
➢ The main street restored
is 46.4 min. eastward.

19.2min.
eastward

Taikyokudem(Shrine of Pole star)

19.2 min.
eastward(6km)

46.4 min.
eastward

Round Hill 円丘【銭国祥 「漢魏洛陽城の北魏宮
城中枢南部の共同調査」】
52©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4852)
and direction of the ruins

Later Hun
後漢

Cao Wei曹魏亢宿Northern Wei Kang xiu
北魏

胃宿
Wei xiu
Round Hill ⇒ South Gate
(Northern Wei Luoyang)氐宿Di xiuNorthern Wei Luoyang Road
(Later Han Luoyang Castle)
53【緯度設定：34.75°(洛陽)】©2022 S.Takesako

Northern Wei Luoyang Castle(from North)

円丘Rounded hill

大路
Main street

True North

太極殿跡 ( Taikyokuden )Ruin of Palace of the Pole star54

【http://wap.art.ifeng.com/?app=system&controller=artmobile&action=content&contentid=3508069】©2022 S.Takesako

Ruins from the Later Han to the Northern and Southern
Dynasties ：Pole Star(HR4893)
Chinese constellations based on the identification of the original map of the Jin dynasty(created in early Tang Dynasty).
Kitora勾陳(6星)
Pole star(HR424)
α UMi (present)

北極(5星)
North Pole (5stars)
Pole star(HR4893)(隋/唐⇒宋/明) (550- 1600 )Takamatsuzuka

四輔 (4星)Pole star (HR4852)(後漢⇒晋⇒南北朝) (0 to 550)

Pole Star

Pole star (HR4927)(春秋⇒漢) (-800 to 0 )55

Note: Position at AD300©2022 S.Takesako

Sui/Daxing castle, Tang/Chang'an castle andMing/Xi'an castle⚫ In 582 AD, Yang Jian of the漢/長安城
Sui Dynasty built Daxing
Hun/
大明宮
Castle to the southeast of
Chang'an castle (Daemingung Palace)
Castle of the Han dynasty.
⚫ Castle is 8.6km north to southand 9.7km east to west.
⚫ The southwestern part of the明・西安城
5.7min.
12.6min.
Xi'an Castle Wall was
Ming/Xi'an castle
eastward
westward
constructed on top of the Sui
and Tang Castle Walls.
➢ Measurement results
Chang'an's West wall
Sui/Daxing,Tang/Chang'an castle:14.9 min. westwards
Xi'an's West wall
14.9min. westward:12.6 min. westward
Xi'an's Eest wall
9.7km
: 5.7 min. eastward
56©2022 S.Takesako

Mongol Empire (Yuan) Shangdu Castle(Measured by the modern Pole Star (αUMi))⚫ Yuan Shangdu was built in
1256, 270 km north of Beijing,
by Kublai of the Mongol
Empire under the command of
Liu Bing Zhong. The outercastle was added later.。
⚫ Marco Polo stayed therearound 1271. He named it
Xanadu (meaning modern day
paradise).
➢ The average direction is
16.1±3.9 minutes westward.
➢ 30.8 min. westward by
HR4893 with Kang xiu.
➢ 15.8 min. westward by themodern Pole Star (αUMi) with
Kui xiu. It is almost the same.
57

2.2km
Outer castle
外城

Palace
宮城
15.2

20.3

12.9

12.9

Inner castle
内城
12.7

22.5

数字は方位(西偏，単位：分)©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4893)
and direction of the Yuan Shangdu Castle

58

【亢宿】
Kang xiu

Year【Latitude：42.37°(Shangdu)】 ©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR424, αUMi)and direction of the Yuan Shangdu Castle

59

【奎宿】
Kui xiuYear【Latitude：42.37°(Shangdu)】 ©2022 S.Takesako

The direction of Yuan Dadu and Zhongdu⚫ Beijing was called Dadu (built ⚫ Yuan Zhongdu was built by Wuzong inin 1267) in the Yuan Dynasty.
1307, about 210 km northwest of Beijing.
Abaut2°12min.
westward
0.8km

Abut 2°35min westward
Outer wall

Inner wall
159.8

134.0

128.7

149.2
Palace

155.0

天安門

157.3

154.4

162.9

161.2

60

©2022 S.Takesako

Direction of Yingchang Castle
and positional relation of castles⚫ Yingchang Castle was built
around 1270 on the shores ofDalai Noor Lake, about 100km
north of Shangdu.
2°22 min. westward

2°22min.westward
Yingchang
応昌路(1270)
103km
16min. westward
Shangdu上都(1256)
177km

152.6

131.1

2°35min. westward
Zhongdu中都(1307)

274km

216km

0.65km61

2°12min. westward
Dadu
大都(北京,1267)©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4893, αUMi)and direction of the Yuan Dadu Castle

62

Dadu
大都(北京,1267)【心宿】
Xin xiuYear【Latitude：39.92°(Beiging)】©2022 S.Takesako

Orientation of the capital castles of the Mongol Empire
Direction of castles and calculated value (HR4893)
Direction from true north.(min. ,+: westward)

Orientation of Ger(11-16c)[Zhongdu]

North[Yingchang](The steps in the direction line are
due to the difference in latitude.)

Dadu west wall

[Dadu]

Castles in the Mongol Empire
were intentionally built awayfrom true north.
South

Year
63

心宿
Xin xiu

Entrance【海日汗「ゲルの方位についての研究」(2004)より】

The direction of the capital castle of the Mongol
Empire (Yuan) is unique to Mongolia©2022 S.Takesako

The end of True north measurement by Pole star
(Ming dynasty Zhongdu)
Ming/Zhongdu(32.88°N 117.54°E)⚫ Zhongdu, 150 km northwest of
Nanjing, construction started in
1369.

Approx. 4°eastward⚫ Six years later, construction was
stopped and Nanjing became theofficial capital.
⚫ The direction is deviated to theeast by about 4°.
⇒not the Pole Star, but thecompass is used for measurement.
(approx. 5.5° eastward of true
north at 120° east longitude)

0.9km

64

©2022 S.Takesako

Summary of Measured direction
and Calculated direction of Historic Sites in China
Summary of Measured and Calculated
direction of Historic Sites in China

Comparison of Measured and Calculated
Directions of Historic Sites in China*1: Value quoted from the papers.
The deflection of the central axis of the Mausoleum of the First Emperor is based on
Masahiro Etaya et al. (2014) p.133. The measured values forAn gate of Chang'an toFive Altars, Five Altars and Changling are from Huang Xiaofen (2006) p.49, 44, 46,
respectively. Actual measurements in Former Han Chang'an Castle are based on Takao
Uno (2010) p.72. The value of Yangrling is based on Takao Uno (2010) p.69. The
measured value of Dadu West Wall (remaining part) is based on Takao Uno (2008)
p.185.*2: Average is -0.2±3.8(σ) minutes

65

Note to left table:
Those with values for direction and distance are the calculated values of the direction
and distance as seen from the place in the column above. A positive direction deviates
to the west from true north, and a negative direction deviates to the east. The measured
position of An Gate in Chang'an Castle is based on Huang Xiaofen (2006) p.44. Others
are measurements around February 2021 by the author's Google Earth Pro. Only the
Xi'an Castle Wall is based on the July 30, 2021 version of the image. It may change dueto the update of the image used by Google.

©2022 S.Takesako

６． Verification of the orientation ofancient remains in Japan66©2022 S.Takesako

Directions of Japanese capitals and main roads
*1
Ruins
史跡

( 参) 太子道( 筋違道)

*2

Year
年代

Rectangularcoordinates
直角座標方位*3

Correction
座標補正

Direction
from方位
TN
真北か
らの

*4
Sources
方位の
出典

?

西

約20度 奈文研( 2007) p.196( 参) 法隆寺( 若草伽藍跡)

607

西約20度 奈文研( 2007) p.196

*5

630

西

639

－

( 正方位) 百済寺より筆者推定

西32分43秒 本書・第三章５項参照－( 正方位) 林部 均( 2008) p.37

飛鳥岡本宮
百済宮

大和・中ツ 道( 639)*5飛鳥板蓋宮
前期難波宮( 中軸線)

650

難波大道中軸線( 653)

後飛鳥岡本宮655

大和・下ツ 道( A区間)

*6*6

大和・下ツ 道( B区間)

( 653)( 655)

大和・下ツ 道( C 区間)( 656)

横大路*5

飛鳥浄御原宮藤原京( 条坊最適方格)
平城京( 条坊最適方格)
大宰府政庁Ⅱ期( 中軸線)

26分31秒

6分12秒

643( 653)
672
672－39分56秒

16分17秒

東

23分39秒 李陽浩( 2005) p.93

－42分39秒

16分17秒

東

26分22秒 李陽浩( 2005) p.94－

( 正方位) 林部 均( 2008) p.96

15分36秒

6分56秒

西

22分32秒 本書・第四章２項参照

35分51秒

6分56秒

西

42分47秒 本書・第四章２項参照

東

40分 本書・第四章２項参照

西

28分 本書・第四章5項参照－( 正方位) 林部 均( 2008) p.122

*6

*7

708
*8

約20度 林部 均( 2008) p.37

28分21秒

6分32秒

西

34分53秒 入倉徳裕( 2013) p.180

14分15秒

6分56秒

西

21分11秒 入倉徳裕( 2013) p.180－34分24秒

16分04秒

東

18分20秒 井上信正( 2009) p.19

－32分31秒

16分17秒

東

16分14秒 李陽浩( 2005) p.93

後期難波宮( 中軸線)

( 713)
726

長岡京( 条坊最適方格)784－3分44秒

10分12秒

西

6分28秒 岩松保( 1996) p.21

平安京( 条坊最適方格)793

14分23秒

8分52秒

西

23分15秒 辻純一( 1994) p.115

平安京白河街区( 今朱雀)

1075

－49分30秒

7分38秒

東

41分52秒 濱崎一志( 1994) p.130

Ruins ofTrue North
Direction

Omi Otsunomiya (667, about 1.5 degrees to the west) and Kunikyo (740, about 1 degree to the west),
which have large swings, were excluded.
67©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4893)
and direction of the ruins of Japan

(

真
北
か
ら
の
方
位
分
、
正
は
西
偏
、
負
は
東
偏

水落遺跡
Mizuochi

中ツ道
Nakatsumichi

唐・長安城の方位
Tang's Chang'an

藤原京
Fujiwara

下ツ道
Shimotsumichi
Replacement of
Appointed Star
(Enthronement ofemperorSaimei,655)

前期難波宮
Early Naniwa)

68

Winter Sky

Arrival ofmeasurement methos

平城京
Heijyou

平安京
Heian

長岡京
Nagaoka

後期難波宮
Later Naniwa

Replacement of
Appointed Star
(around 780)

石神遺跡
Ishigamo
Summer sky

1st Envoy 2nd Envoy 詳細は、「古代の正方位測量法(第三版)」PDF版(2022/04/01)を参照。
to Tang
to Tang【Latitude：34.75°(Nara/Kyoto)】 ©2022 S.Takesako

Estimation of dating from the orientation ofhistoric remains
Differences in orientation and date of historic sites and remains
Historic
史跡sites

年代
Year

Estimated year Diff.(Y)Diff.(m)Direction
Direction分)(m) 差(
Xiu Est.
遺構の 方位 定星
計算方位(分) 推定中心年差( 年)( 大和・中ツ 道)( 639)

32分43秒 星宿

30.44

2.3

632

7

前期難波宮( 中軸線)

650

－23分39秒 虚宿-27.75

4.1

662

-12

難波大道中軸線( 653)－26分22秒 虚宿-26.73

0.4

654

-1

大和・下ツ 道( A区間)

( 653)

22分32秒 星宿

25.84

-3.3

662

-9

大和・下ツ 道（B区間)( 655)

42分47秒 柳宿

40.77

2.0

649

6

大和・下ツ 道( C 区間)( 656)－40分 女宿-38.83

-1.2

653

3

大和・横大路( 653)

28分 星宿

25.84

-3.3

646

7

藤原京( 条坊最適方格)672

34分53秒 柳宿

34.38

0.5

671

1

平城京( 条坊最適方格)708

21分11秒 柳宿

20.86

0.3

707

1

大宰府政庁Ⅱ期( 中軸線)

( 713)－18分20秒 女宿-17.24

-1.1

710

3

後期難波宮( 中軸線)

726

－16分14秒 女宿-12.35

-3.9

716

10

長岡京( 条坊最適方格)784

6分28秒 女宿

9.35

-2.9

777

7

平安京( 条坊最適方格)793

23分15秒 参宿

19.95

3.3

784

9

平安京白河街区( 今朱雀) * 1

1075－41分52秒 昴宿-40.43

-1.4

1080

-5

平均

-0.3±2.5( σ)1.9±6.5( σ)The error (σ) between the actual date of the site and the estimated datebased on the orientation is about ±7 years.
⇒It is possible to estimate the date based on the orientation of the remains.
However, since there are multiple date in one direction, it is necessary tonarrow down the estimated date.
69©2022 S.TakesakoA quick reference chart of current directions andestimated years (630-829, unit: minutes)
西暦

70

西暦

虚宿

女宿

柳宿

西暦

女宿

柳宿

西暦

女宿

柳宿

西暦

柳宿

西暦

箕宿

参宿

630 - 34.6

虚宿

女宿

33.3

663

- 23.4- 36.2

37.6

696 - 23.7

25.2

730 - 10.9

12.5

763

1.5

0.1

796

- 16.018.7

631 - 34.3

32.9

664

- 23.0- 35.837.2

697 - 23.3

24.8

731 - 10.5

12.1

764

1.9

- 0.3

797

- 15.6

18.3

632 - 33.9

32.6

665

- 22.7- 35.436.9

698 - 22.9

24.5

732

- 10.1

11.7

765

2.2

- 0.6

798

- 15.217.9

633 - 33.6

32.3

666

- 22.3- 35.1

36.5

699 - 22.6

24.1

733

- 9.8

11.3

766

2.6

- 1.0

799

- 14.817.5

634 - 33.3

31.9

667

- 22.0- 34.736.1

700 - 22.2

23.7

734

- 9.4

11.0

767

3.0

- 1.4

800

- 14.417.2

635 - 32.9

31.6

668

- 21.7- 34.335.7

701- 21.8

23.3

735

- 9.0

10.6

768

3.4

- 1.8

801

- 14.016.8

636 - 32.6

31.3

669

- 21.3- 33.935.4

702- 21.4

23.0

736

- 8.6

10.2

769

3.7

- 2.1

802

- 13.7

16.4

637 - 32.2

31.0

670

- 21.0- 33.535.0

703- 21.1

22.6

737

- 8.2

9.8

770

- 26.2

4.1

28.5

- 2.5

803

- 13.316.0

638- 31.930.6

671- 20.6- 33.2

34.6

704 - 20.7

22.2

738

- 7.9

9.5

771

- 25.8

4.5

28.1

- 2.9

804

- 12.915.7

639- 31.530.3

672- 20.3- 32.834.2

705 - 20.3

21.8

739

- 7.5

9.1

772

- 25.4

4.9

27.7

- 3.3

805

- 12.515.3

640- 31.230.0

673- 20.0- 32.433.9

706- 19.9

21.5

740

- 7.1

8.7

773

- 25.0

5.2

27.3

- 3.6

806

- 12.114.9

641 - 30.9

29.6

674

- 19.6- 32.033.5

707- 19.5

21.1

741

- 6.7

8.3

774

- 24.6

5.6

26.9

- 4.0

807

- 11.714.5

642 - 30.5

29.3

675

- 19.3- 31.733.1

708- 19.2

20.7

742

- 6.4

8.0

775

- 24.3

6.0

26.6

- 4.4

808

- 11.314.2

643 - 30.2

29.0

676

- 18.9- 31.332.7

709- 18.8

20.3

743

- 6.0

7.6

776

- 23.9

6.3

26.2

- 4.8

809

- 10.913.8

644 - 29.8

28.7

677

- 18.6- 30.932.4

710- 18.4

20.0

744

- 5.6

7.2

777

- 23.5

6.7

25.8

- 5.1

810

- 10.513.4

645 - 29.5

28.3

678

- 18.3- 30.532.0

711- 18.0

19.6

745

- 5.2

6.8

778

- 23.1

7.1

25.4

- 5.5

811

- 10.113.0

646- 29.128.0

679- 17.9- 30.1

31.6

712- 17.7

19.2

746

- 4.9

6.5

779

- 22.7

7.5

25.1

- 5.9

812

- 9.7

12.7

647 - 28.8

27.7

680

- 17.6- 29.831.2

713- 17.3

18.8

747

- 4.5

6.1

780

- 22.3

7.8

24.7

- 6.2

813

- 9.3

12.3

648 - 28.5

27.4

681

- 17.3- 29.430.8

714- 16.9

18.5

748

- 4.1

5.7

781

- 21.9

8.2

24.3

- 6.6

814

- 8.9

11.9

649

27.0

42.9

682

- 16.9- 29.030.5

715- 16.5

18.1

749

- 3.8

5.4

782

- 21.5

8.6

23.9

- 7.0

815

- 8.5

11.5

- 28.1

星宿

柳宿

箕宿

女宿

参宿

650 - 27.8

- 41.2

26.7

42.5

683

- 16.6- 28.630.1

716- 16.1

17.7

750

- 3.4

5.0

783

- 21.1

9.0

23.6

- 7.4

816

- 8.1

11.1

651 - 27.4

- 40.8

26.4

42.1

684

- 16.2- 28.229.7

717- 15.8

17.3

751

- 3.0

4.6

784

- 20.7

9.3

23.2

- 7.7

817

- 7.7

10.8

652

- 27.1- 40.4

26.0

41.8

685

- 15.9- 27.929.3

718- 15.4

17.0

752

- 2.6

4.2

785

- 20.3

9.7

22.8

- 8.1

818

- 7.4

10.4

653 - 26.8

- 40.0

25.7

41.4

686

- 15.6- 27.529.0

719- 15.0

16.6

753

- 2.3

3.9

786

- 19.9

10.1

22.4

- 8.5

819

- 7.0

10.0

654 - 26.4

- 39.6

25.4

41.0

687

- 15.2- 27.128.6

720- 14.6

16.2

754

- 1.9

3.5

787

- 19.5

10.4

22.1

- 8.9

820

- 6.6

9.6

655

- 26.1- 39.3

25.1

40.6

688

- 14.9- 26.728.2

721- 14.3

15.8

755

- 1.5

3.1

788

- 19.2

10.8

21.7

- 9.2

821

- 6.2

9.3

656 - 25.7

- 38.9

24.7

40.2

689

- 14.6- 26.327.8

722- 13.9

15.5

756

- 1.1

2.7

789

- 18.8

11.2

21.3

- 9.6

822

- 5.8

8.9

657 - 25.4

- 38.5

24.4

39.9

690

- 14.2- 26.027.5

723- 13.5

15.1

757

- 0.8

2.4

790

- 18.4

11.6

20.9- 10.0

823

- 5.4

8.5

658

- 25.1- 38.1

24.1

39.5

691

- 13.9- 25.627.1

724- 13.1

14.7

758

- 0.4

2.0

791

- 18.0

20.6

824

- 5.0

8.1

659 - 24.7

- 37.7

23.7

39.1

692

- 13.5- 25.226.7

725- 12.8

14.3

759

0.0

1.6

792

- 17.6

20.2

825

- 4.6

7.8

660 - 24.4

- 37.3

23.4

38.7

693

- 13.2- 24.826.3

726- 12.4

14.0

760

0.4

1.2

793

- 17.2

19.8

826

- 4.2

7.4

661 - 24.0

- 37.0

23.1

38.4

694

- 12.9- 24.526.0

727- 12.0

13.6

761

0.7

0.9

794

- 16.8

19.4

827

- 3.8

7.0

662 - 23.7

- 36.6

22.8

38.0

695

- 12.5- 24.1

25.6

728- 11.6

13.2

762

1.1

0.5

795

- 16.4

19.1

828

- 3.4

6.6

663 - 23.4

- 36.2

22.4

37.6

696

- 12.2- 23.725.2

729- 11.3

12.8

763

1.5

0.1

796

- 16.0

18.7

829

- 3.0

6.3

Note: Pole star is HR4893. Calculated on July 1 at 34.75° latitude. Positive Azimuth is west
deviated and Negative is east. Also use the azimuth line diagram . This table is based on the
results of verification of the orientation of Japanese remains that we know at this time. ©2022 S.Takesako

７． Example of dating by the orientationof excavated remains

71©2022 S.TakesakoEmperor Monmu,大官大寺(Daikandaiji Temple)⚫ It was founded during the reign ofEmperor Monmu (697-707).
⚫ The offset of the central axis of thetemple is about 22 min. and 13 sec.
westward of true north .
➢ The Pole Star (HR4893) and the Liu
xiu leading star give an estimatedyear of 704±7, which coincides withthe time when Emperor Monmu's
Daikandaiji Temple was built.

↑ Mount Kaguyama

金堂
the main hall

塔
Tower
中門
Middle gate

➢ This temple is located in Fujiwara【図と方位は奈文研「大官大寺第2次の調査」 (1976)より】
kyo, but the direction is almost thesame as Heijo-kyo of the same period.
↓ Palace of Asuka
72©2022 S.Takesako

Orientation of remains of Otsukyo-related ruins
According to Hiromichi Hayashi(2005)① Otsukyou：85 min. eastward② South shiga ten.：85 min. eastward③ Hannokihara ruin：85 min. eastward⇒Measured by Bigg Dipper 4th star
④ Soufuku Temple：
North ridge Mirokudo：8°eastward
Middle ridge Main hall：8°40' to 9°e.
South ridge Main hall:：3°easetward(⇒Corrected to 25 min. westward)
auditorium：2°30' eastward(⇒Corrected to 21 min. westward)(Kyodo： 80 min westward)⑤ Anoutemple：
rebuilt cathedral/auditorium：2°30' min. eastward
Main hall/Tower：(5min. weastward)⇒If they were built at Otsukyou era,the direction should be around 23min.
73
eastward. Re-measurement is required.

⑤穴太廃寺跡Anou temple④崇福寺跡
Soufuku Temple

Are of 85
min. offset
榿木原遺跡③
Hannokihara②南志賀廃寺跡
south shiga temple①大津京錦織遺跡
Otsukyou【Note：Corrected based pm 宮原健吾/宇野隆夫/臼井正「方位からみた大津宮と崇福寺」(2006)より。】 ©2022 S.Takesako

The direction of Otsukyo(measured by the Big Dipper 4th star (HR4660))
Direction from true north.(min. ,+: west -: East)

Otsukyo【軫宿】
Zhen xiu

Spring's leading star)74

Big Dipper
HR4660【女宿】
Nu xiuPole starHR4893

(

真
北
か
ら
の
方
位
分
、
正
は
西
偏
、
負
は
東
偏

85min. westward

Autumn's leading star

23min. eastward【壁宿】
Kawahara Temple

big Dipper
HR4660

西暦Bi xiuEmperor Tengi replaced
Hokushin (Pole Star) with
the Big Dipper.

Meghrez δUMa(HR4660)【Latitude：34.75°(Nara/Kyoto)】©2022 S.Takesako

Azimuth of 川原寺(Kawahara Temple) in Asuka⚫ Temple built after the
Asuka Itafutamiya fire(655) at the ruins of
Kawahara Palace⚫ It was erected after thedeath of Emperor Saimei(661) to pray for his soul
⚫ 667 Capital moved to
Otsukyo⚫ In the second year of thereign of Emperor Tenmu(673), there is an article
about copying Issaikyo at
Kawara-dera Temple.
➢ Gate；21min. eastward➢ Corridor:17min. eastward➢ Tower(Kamakura)：44min.
75
eastward⇒1244±7

Tower：44min. eastward

Corridor: 17min. eastward
middle gate: 21min.eastward【「川原寺寺域北限の調査」奈良文化財研究所(2004)p.9より】

測定方位は，宮原健吾/宇野隆夫/臼井正「方位からみた大津宮と崇福寺」(2006)より。
©2022 S.Takesako

Direction from true north.(min. ,+: west -: East)

Azimuth line by Pole star (HR4893)
and direction of the ruins of Kawahara Temple

(

真
北
か
ら
の
方
位
分
，
正
は
西
偏
，
負
は
東
偏

西暦年代

Gate and corridor

)

Tower

76

【虚宿】
Xu xiuMeasured by Bi Dipper【胃宿】
Wei xiu【Latitude：34.75°(Nara/Kyoto)】 ©2022 S.Takesako

Ruin of 崇福寺 (Soufukuji, South ridge)⇒ 梵釈寺 ( Bonsyakuji )⚫ It is believed that the temple
site on the south ridge ofSofuku-ji Temple in Otsu City
may be Bonshaku-ji Temple(786) founded by Emperor
Kanmu, but this has not been
confirmed.

➢ Main hall：25 min. westward⇒year 779±7➢ Auditorium；21min. westward⇒year 790±7➢ Warehouse of Buddhist
script：80 min. westward⇒Otukyo period⚫ The central axis (averagevalue) of the construction
direction matches the age of77
Bonshakuji Temple.

Warehouse of Buddhist script:
80 minutes westward

Main hall:
25 min. westward

Auditorium:
21 min. westward【現地説明パネルより】【測定方位は宮原健吾/宇野隆夫/臼井正「方位からみた大津宮と崇福寺」(2006)より】©2022 S.Takesako

８． Dating of the ancient straight roadby its direction*The estimated age of the ancient road here is the date ofconstruction of the true north-south straight road where remains
remain, and does not deny the existence of the existing road
before that.

78©2022 S.Takesako

The dating of ancient roads⚫ General methods for estimating the date of excavated remains➢➢➢

Strata overlap
Overlapping Remains
Date of excavated earthenware and roof tiles⚫ Why dating of road is so difficult
➢
➢
➢

⚫

⚫

79

Very few relics have been found
Necessity to assume influx from other lands even if relics are excavatedLong-used roads may be repaired

Even if pottery is excavated in one place on a road, there is a problem inusing it for estimation of the entire road of several kilometers. Until now,
estimates of the date of roads have been inferences based on circumstantial
evidence based on documents, etc., with few excavation results. Therefore,
there is no archaeological basis for the popular theory.
The direction of the road is the only physical evidence that can identify
the date of the "entire road". The estimation of the construction datebased on the direction of the true north-south road is the first method of
estimating the actual date based on scientific grounds.
©2022 S.Takesako

Dating of the three ancient roads in the Yamato Plain⚫ According to the established theory, thethree ancient Yamato roads (Kamitsu-michi,
Nakatsu-michi, and Shimotsu-michi) areconsidered to have been constructed at
approximately the same time, based on the
Shimotsu-michi, since the distance between
them is the same.
⚫ The Shimotsu-michi Route was built startingfrom the north of Maruyama Burial Mound(common theory).

平城京
Heijyou-kyo

北の横大路
Horizontal main streetof the North下ツ道
Shimotsu-michi⚫ Dating of the road already announced.

中ツ道
Nakatsu-michi➢ Based on these popular theories, it isbelieved that the road was built during thereign of Emperor Suiko (biginning of the
7th century), and is said to be closely
related to Maruyama Burial Mound.

横大路
Yoko-oji➢ The theory in the middle of the 7th century,
which is based mainly on the true northorientation (after Itabuki no Miya).

丸山古墳
Maruyama Burial Mound

上ツ道
Kamitsu-michi

丸山
古墳

80

©2022 S.Takesako

Direction of the Shimotsumichi
⚫

⚫

⚫

⚫
81

Shimotsu-michi is an ancient straightroad that became the basis of Fujiwarakyo and Heijo-kyo.
The Direction of Shimotsu-michi is said
to be 24.4 minutes westward on average,
connecting the Yagi, Kashihara City site
and the Suzaku gate.
If you calculate the direction by road(latitude and longitude),➢ Yagi ⇒ Suzaku Gate ： 24.2min.
➢ Karunochimata ⇒ Gate ： 25.4min.
➢ Mruyama Mound ⇒ Gate ：24.6min.
It is believed that they were built startingfrom the Maruyama Burial Mound in thesame direction.

平城京
Hijyoukyou
朱雀門
Suzaku Gate

24.4 min. westward
Shimotsumichi

藤原京
Fujiwarakyou
Yagi

丸山
古墳

丸山古墳
Maruyama
Burial Mound©2022 S.Takesako

Data of the Shimotsumichi
Shimotsumichi (Center of the side ditch)⚫

The offset of the C section averages thestart and end points, making it difficult
to find the deflection peculiar to the B
and C sections.

朱雀門
Suzaku-gate
A

B
C

Section A

Data of the Shimotsumichi
D
世界測地系
発掘場所

Excavation
data

発掘年次

Y座標
東側溝心

西側溝心

中心

X座標

参照文献

A

朱雀門

-18836.98-18859.78-18848.38 -145601.50 [12]p.20

B

朱雀大路(五条-六条間)-18826.30-18849.71-18838.00 -147486.99 [12]p.20-18832.86-18820.71 -151328.51 [12]p.20

C

稗田遺跡

-18808.56

D

八条遺跡-18794.30

E藤原京右京四条五坊

橿教委1999-5次

F

藤原京右京七条四坊

藤原京第58-5次(1988)

G

藤原京右京八条五坊

橿教委1995-7次-18745.14-18732.39 -167137.37 [5] p.48

H

藤原京右京十条五坊

橿教委2016-8次-18740.00-18727.25 -167599.00 [5] p.48

-18807.05 -154670.00 [21]p.37-18775.39-18721.49-18762.64 -164223.45 [5] p.48
-18734.24 -166974.38 [13]p.43

C区 軽衢-18720.63 -168248.86 筆者

C区 道路二又-18725.45 -168585.10 筆者

C区 丸山古墳削減点-18730.41 -168952.85 筆者

C区 飛鳥入口-18732.34 -169138.35 筆者

YagiIntersection
with Taishi-michi

E
Section B EFG

HSection C

Maruyama Burial Mound[world geodetic system]

82©2022 S.Takesako

Consistency of the construction date of the three
sections with the Nihonshoki (Chronicles of Japan)
⚫
⚫

⚫

⚫

83

Section A: Road to North➢ 白雉四年（653）脩治処処大道
Section B: Road to Oharidano-miya➢ 斉明天皇元年（655）
小墾田造起宮闕、擬将瓦覆。
又於深山広谷。擬造宮殿之材。
朽爛者多。遂止弗作。

Section C: Road to Asukano-miya➢ 斉明天皇二年（656）
遂起宮室。号曰後飛鳥岡本宮。
➢ 自香山西至石上山。狂心渠。
Sections B and C are clearly
constructed in the Saimei period(655-661) from their orientation.

太子道
Taishi michi

SectionA:22.6min. westward
Estimated date: around 654
上ツ道
Kamitsumichi
中ツ道
Nakatsumichi

札の辻
Fudano-tsuji

横大路
Yoko-oji

Section B:42.8min. eastward
Estimated date:655~656
狂心の渠
Taburegogorono-mizo
軽衢Karuno-chimata小墾田宮

丸山
古墳

Oharidanomiya
Section C: 40min. eastward
Estimated Date: 655~660
飛鳥宮への道後飛鳥岡本宮Asukano-miya©2022 S.Takesako

Dating of Nakatsumichi by its direction⚫ Nakatsumichi's actual route⑯
was 100m west of the
東四坊東小路Heijyoukyo⑲
平城京
asumed route. ⇒ Unrelated
東四坊大路
九条大路 ①to FujiwaraKyo's jobo.。
Pond of Koshita⚫ The equally spaced road was 十条大路②
excavated
京道
pointsnot Nakatsumichi, but Jobo
Assumed route③(24.4min.
west wardof Fujiwarakyo.
Actual route ④ 100m west
Dating: 657±7)(32.7min. westward➢ The direction is 32.7 min.
Dating:632±7 )⑤westward, and 8.3 min.
Shrines along with route 51⑥⑦
県道51号 沿いの神社
westward of Shimotsumichi.
⑧
箸墓古墳➢ The estimated date is2213m(上ツ道迄)⑨2024m(下ツ道迄)632±7 year. ⇒Overlaps⑩
with Emperor Jomei's
藤原京北端(一条北大路)
下ツ道から2118m⑪
Kudara Palace(639)
百済宮推定地⑫➢ The three ancient roads was
横大路(三条大路)
Kudarano-miya⑬
天香久山々頂not evenly spaced, nor was
Fujiwarakyo⑭ (国常立神社) 藤原京
it the same period.
東二坊大路⑮（Direction＝26.5+6.2＝32.7min.)84[世界測地系] ©2022 S.Takesako

Dating of Yoko-oji (Horizontal main street)by its direction⚫ Based on its Direction, Yoko-oji is thought to have been built in 653,
just like the other main roadts.
[world geodetic system]

West section(8.6km)：27.5min. westward
Dating:：648±(7＋α)

札の辻 (Fudanotsuji)
East section(4.2km)：28.4min. Westward
Dating ： 645±(7＋α)(Trace of Current road)

α： Error in determining the east-west line from the north-south line。
Nakatsumichi
Shimoyumivhi 中ツ道 Kamitsumichi
下ツ道
(639)
上ツ道
(653)
(653)
Yoko-oji
横大路
85

Fudanotsuji
札の辻©2022 S.Takesako

Dating of Kitano-yoko-oji(Horizontal main street of north)by its direction⚫ Direction：➢ Beijyu Br. to Wani Shrine：13.2 min. westward➢ Direction by the road
Houryuuji
法隆寺：11.9 min. westward⚫ Dating(around AD730)
13.2min.：AD728±(7+α)
11.9min.：AD731±(7+α)

Nakatsumichi
中ツ道Shimotsumichi
Kamitsumichi
下ツ道
上ツ道
Yamato river
大和川⚫ With the construction of
Naniwa Palace during the lastyears of Emperor Shomu(around 726-732), a straighteast-west road was
redeveloped.

⚫ The straight east-west road,which was developed at thesame time as the
Shimotsumichi was repaired.
86

Wanishimo shrine
和爾下神社

Beijyu-Br. Kitano-yoko-ojo
北の横大路
米寿橋

11.9min. westward

Beijyu-Br.
米寿橋

Wanishimo shrine
和爾下神社

13.2min. westward(Trace of the current road)[world geodetic system]©2022 S.Takesako

Dating of Naniwa-daido by its direction⚫ Naniwa-daido starts from
Naniwa Palace and continues
south. Its direction coincides
with the 26.8 min east directionin 653, and it was built at thesame time as Shimotsumichi.
⚫ The direction measurement is
9.8 km from the Naniwa Palaceto the Yamato River excavation
point.
➢ 26.2 min. eastward➢ Dating: AD 648 to 654⚫ It is also consistent with thedating (from the middle of the
7th century) based on the
excavation (overlapping of87
earthenware and strata).

Naniwanomiya
Daigokuden
難波宮
内裏前殿
(大極殿)

側溝
Naniwa-daido
難波大道(発掘現場の写真は大阪府HPより)

側溝
路面
Excavation
Pont
難波大道
発掘地点

©2022 S.Takesako

９． The introduction of Hokushin ruling thought
to Japan88©2022 S.Takesako

The true north orientation of the palace signifies theintroduction of Hokushin ruling thought.
⚫ In China, from the Chunqiu period to the Middle Ages, theconstruction of the capital's castle used the direction measurement
method by the Pole Star.
⚫ The stage (castle, palace, Taigokuden) measured by the Pole Staris the embodiment of the existence of the Heavenly Emperor(Hokushin/Pole Star).
⚫ By performing dynastic ceremonies on this stage, the emperor
legitimizes the rule that received the ``Destiny of the Heavenly
Emperor'' (Hokushin ruling thought).This is the reason why theenthronement ceremony is held at the Daigokuden in Japan.
⚫ The correct orientation of palaces in Japan also means theintroduction of the Hokushin ruling idea, not landscapemaintenance.
➢ The correct orientation of palaces ⇒Daigokuden⇒coronation
ceremony⇒The "Tnno" was born
89©2022 S.Takesako

The Hokushin ruling idea of China
was transmitted to Japan as a whole
The Hokushin
ruling thoughtJapanand theoctagonal
construction
643：舒明天皇陵
burial moundmethod were天皇
星図(618～649)に天皇星transferred toJapan as a whole. Four-way
642：皇極天皇
worship

China
Pyramid

(Hun)

皇帝
royal
ceremonies

throne太極殿(Wei235)

Correct orientation of
Palace Castle
Correct orientation of
Capital Castle(八角墳以前)大極殿

643：板蓋宮(639：百済宮)

Correct orientation of
Palace(Chunqiu)

Castle ⇒ Long Road

Measuerment by Pole star(632±7)
Measuerment by Pole star (632±7)

Hokushin ruling thought

Hokushin ruling thought

Without the idea of Hokushin ruling,
there is no castle or palace in thecorrect orientation.
90

high throne

The Hokushin ruling idea was introduced
by students to sui who returned to Japan in632, and the 'Emperor' who deified the'Great King' was born.

詳細は、「古代の正方位測量法(第三版)」PDF版(2022/04/01)を参照。

©2022 S.Takesako

When did the idea of the Hokushin rule reach Japan?
⚫ Correctly oriented palaces and roads are measured by Pole star,➢ It is presumed that the ideas and basic technology of the
Hokushin ruling thought were introduced between Asuka
Okamoto Palace(630) and Kudara Palace(640).
➢ A star chart with the 'Emperor' star was also introduced.
推古舒明
小墾田宮 岡本宮 百済宮（603） (630) (640)

Octagonal burial
mound

☓

－

Palace ofPole star☓－

True northoriented Palace

(☓)

☓

91

孝徳
難波宮
(652)

斉明
後岡本宮
(656)

天智
大津宮
(666)

○

－

☓
(round)

○

○

○

(○)

○

○

○

？

○
(SB7910)○85min.
West○○(Assume) (書紀) (内裏前殿) (SB7910)(○)(20°西偏) (Assume)

True northoriented Road
Measured byPole Star

皇極
板蓋宮
(643)

○

(Nakatsu)

☓

○

○

○

Jyoubouroad○○(Naniwa) (Shimotsu)

○

(☓)

○

天武
持統
浄御原宮
藤原京
(672)
(694)

○
(Assume)○○Big
Dipper

詳細は、「古代の正方位測量法(第三版)」PDF版(2022/04/01)を参照。

○○©2022 S.Takesako

The etymology of 『天皇』(Emperor)
may be from 『格子月進図』(star chart for moon)
四輔

北極
極星

勾陳
天皇
"The Tenno(Emperor) is thecenter of theheavens and is the
god of the East."【 別冊 太陽 No.73(1991) p.38より】

92

Tenno-Tai-tei（天皇大帝) is in the journalof the book of Jin, but this book was not
yet completed at the time of Emperor Jomei.
China 皇帝 ⇒ Japan 天皇©2022 S.Takesako

10． Summary

93©2022 S.Takesako

The Meaning of the Capital Castle and Palacein the Correct Orientation
HR4852

北極星：HR4927

HR4893(HR424:元上都のみ)

Taikyokuden era

Disappear

The correct orientation of castle

China

春
秋

宋

実
践
『
営 的
造 儀
法 礼
式
』 論

元

明

明
・
西
安
・
東
城
壁
１
３
７
０

元 応
・ 昌
上大路 中
都都城 都
１１１ １
２２２ ３
５６７ ０
６７０ ７

隋
・
大
興
城
Hokushin
唐・ ruling thought
長Daigokuden era
安
城
５
飛
８
奈
平
２
鳥
良
安

(

)
)
)
)

)

(

鎌
倉

Japan

)

前 後藤 大平大後 長 平 白川
百飛
飛原 宰城宰期 岡 安 河原
鳥済板期
鳥京 府京府・ 京 京 街寺
・
宮蓋難 岡
区再
条 政難
坊７庁波 ７ ７／宮波 本
１建
０ 宮 ８ ９中 宮宮
０塔
８ （ ４ ３ ７１
ツ ６／
７
道 ５下
５２
『 ２
ツ
４
０道
平 ６
４
城
）
／・
頃
京
難上
造
波ツ
営
大道
No correct orientationの道詔
castle in Samurai Period
』

)

)

)

(

(

(

(

)

(

(

)

『
大
興
城
造
営
の
詔
』

(

In the correct orientation of palace, there
was the Daigokuden, which served as thecentral stage for dynastic ceremonies under
the rule of Hokushin.。

礼宇
論宙
の論
衰的
退儀

(
(
(
(

)
)

)
)

)

Daikyokuden appears(235)

隋
唐

/

)

北北
魏魏
・・
平洛
城陽
城
４５
００
６１

(
(

後
漢
・
洛
陽
城
２
５

(

漢漢
・・
長陽
安陵
城
ＢＢ
ＣＣ
２１
０５
２４

(
(

)

秦
・
始
皇
帝
陵
Ｂ
Ｃ
２
２
１

(

趙
・
王
城
Ｂ
Ｃ
３
８
６

北
魏

漢

秦

(

『『
周詩
礼経
・』
考『
工晏
記子
』春
秋
』

趙

)

)

94

「太極殿の時代/大極殿の時代」
Daigokuden appears(645)の文言は妹尾達彦「コメント2「宮in Asuka
中枢部の形成と展開:大極殿の成立をめぐって」」(2009)より
詳細は、「古代の正方位測量法(第三版)」PDF版(2022/04/01)を参照。

©2022 S.Takesako

end

95

©2022 S.Takesako

How True North Was Measured
by the Pole star in Ancient China