Paper submitted to the 1st International Conference of Asian Network for GIS-based Historical
Studies (ANGIS) at Tokyo University, dated December 1 – 2, 2012
Medieval Cultural Networks of Continental Southeast Asia
- East-West Corridor and its GIS based Historical Studies -
Prof. Mamoru Shibayama
Center for Integrated Area Studies, Kyoto University, Japan
Not to be cited without author’s permission
In Search of East-west Corridor towards New Horizons on GIS-Based Informatics for ANGIS Paper: 2012/12/1
Medieval Cultural Networks of Continental Southeast Asia
- East-West Corridor and its GIS based Historical Studies Prof. Mamoru Shibayama
Center for Integrated Area Studies, Kyoto University, Japan
Abstract
Taking the Indochinese peninsula as the center, the medieval trade networks of Mainland
Southeast Asia extended west from Bay of Bengal to the Indian Ocean and beyond to the
maritime city states of Europe, To the south they reached Malaysia, Indonesia, and other
parts of Maritime Southeast Asia, and to the east they extended to maritime China, the
Korean peninsula, and Japan. Of these networks, this paper focuses on the East-West
Corridor trade network, a land-based route from Myanmar to Thailand and Cambodia. In
addition to an overview of how mapping information known from related documents,
research, and hypotheses were mapped using a GIS (geographical information system), the
paper introduces attempts to gain new knowledge and to verify hypotheses from the
perspective of information studies.
1. The East-West Corridor — a land-based culture and trade network
Trade with Thailand, China, the Ryukyu kingdom, and Japan has been described from the
viewpoint of a Maritime Asia trade network with sea-based routes, but what is the situation
regarding a land-based network centered on Thailand? Consider the period when there was
intermediate trade by the Ryukyu kingdom as examined in the artcle [Shibayama 2012a],
and the period when there were "Shuin-sen" (trading ships licensed by the shogunate) of
Japan, followed by trade with China under Japan's subsequent national policy of isolation.
Virtually all of these periods coincided with the Ayutthaya dynasty in Thailand.
Rather than this period, the present report considers periods that were a little earlier,
introducing cultural and trade networks in and around Thailand from about the 10th
century, to the Sukhothai dynasty (13th century-15th century), and Ayutthaya dynasty (15th
century-18th century). Particular attention is paid to the East-West Corridor in the 11th
century-14th century, focusing on Bay of Bengal-Sukhothai trade routes, the Royal Roads
around Angkor, and trade routes from Tenasserim in southern Myanmar to Ayutthaya
[Shibayama 2012b]. The term "East-West Corridor" is also used for an economic corridor in
today's Indochinese peninsula, largely in Thailand, but that is beyond the scope of this
paper[Kakizaki 2011].
Regarding references concerning the East-West Corridor, in "Tonan Asia shi no
teisetsu wo saikento suru" (Re-examining established theory in Southeast Asian history)
[Ishii 2006] and "'Tozai kairo' ni kansuru oboegaki" (A note on the East-West corridor) [Ishii
2009] Ishii sets out a hypothesis regarding trade routes from Myanmar to Thailand at the
time of the Sukhothai dynasty. His hypothesis includes a description of trade routes crossing
central Thailand to reach Angkor in Cambodia, and then linking to the Maritime Asia
network via the Mekong Delta in southern Vietnam. In addition, research conducted over a
hundred years ago by and in association with the École française d'Extrême-Orient (EFEO)
posited that there were two Royal Roads from Angkor linking with Thailand. Furthermore, a
Thailand-Cambodia joint project is currently working on digs to survey a route between
Angkor and Phimai (Nakorn Ratchasima, Thailand). Sakurai is surveying a route from
Angkor to Aranyaprathet in Thailand, a further route between Angkor and Thailand, and
investigating the history of the Khmer Empire (9th century-13th century)[Sakurai 2012].
The author mapped both the Ishii theory and the Sakurai theory in the GIS to obtain
an overview. In addition 52 thematic maps indicating the extent of rule and control by
different powers in the Indochinese peninsula from the 2th century to the 16th century
[TimeMap Project 2003], the Thailand-Cambodia joint project's list of around 800 sites in
Thailand, and a list of about 350 Khmer sites independently surveyed by the author were all
mapped and layered in the GIS in order to search out East-West Corridor trade and
communication routes.
1
In Search of East-west Corridor towards New Horizons on GIS-Based Informatics for ANGIS Paper: 2012/12/1
1-1. East-West Corridor passing through Sukhothai
In debate over the existence of the East-West Corridor, Ishii started by referring to how
Thailand's historical periods are divided. Until now, researchers have viewed Thailand's
history from a linear perspective, designating the Sukhothai period (13th-14th century),
Ayutthaya period (14th-18th century), Thonburi period (18th century), and Bangkok period
(18th century-the present). However, Ishii asserted that instead of taking this sort of linear
perspective, it was important to think in terms of three categories, (a) Shan cultural area or
Lanna, (b) Mueang Nua (northern states), (c) maritime city states along the Thai coast, and
to take an overview of the political, cultural, and trade relationships between them [Ishii
2006]. From that background, and based on Sukhothai stone inscription No.1 (1292.A.D.),
Ishii theorized that an East-West Corridor passed through Sukhothai, with a route between
Myanmar and Sukhothai going from Martaban in Myanmar via Moulmein, Kawkareik, and
Kyondo, and then Mae Sot in Thailand to Tak, and Sukhothai. Items traded included
elephants, horses, and gold & silvers.
Figure 1. Sukhothai period trade route
[Source: Ishii 2008]
Figure 2. Khmer-style sites, examining
the East-West Corridor
The route is shown in Figure 1. Figure 2 shows the East-West Corridor and Royal Road
mapped by the GIS onto maps showing the Khmer-style sites in the Angkor period from the
time of Suryavarman II to Jayavarman VII. From the Angkor period to the time of the rise of
the Sukhothai dynasty in Thailand, trading occurred along with the transmission of
Mahayana Buddhism and Theravada Buddhism from India and Sri Lanka. Evidence to
support this includes the presence of Khmer-style sites distributed in Thailand, and the
excavation or discovery of structures, artifacts, and other archaeological findings along the
trade route, such as hospitals, rest houses, bridges, iron foundries, salt production, and
ceramics.
Ishii also described a pilgrimage route referenced in Sukhothai stone inscription
No.11 (1350.A.D.), which tells of how the priest Mahathera Srisraddharajaculamuni, who
had been training in northern Thailand, went to Sri Lanka, taking a route from Uttaradit via
Lamphun near Chiang Mai, and then returned to Phitsanulok several years later. The
Mahathera traveled from Lamphun to Tak, crossed into Myanmar from Mae Sot, then took
the route to the Bay of Bengal that will be described below. After spending two years in Sri
Lanka, he came back to Tenasserim from Mergui, one of Myanmar's maritime city states.
From Tenasserim, he crossed the Maw Daung Pass to Prachuap Khiri Kan in Thailand, then
reached Phetchaburi. From there, he traveled via Ratchaburi, Suphan Buri, and Ayutthaya
to arrive back in Phitsanulok.
2
In Search of East-west Corridor towards New Horizons on GIS-Based Informatics for ANGIS Paper: 2012/12/1
Figure 3. The Mahathera's pilgrimage route
from Sukhothai stone inscription
No.11 (1350.A.D.)
Figure 4. Four trade routes to the Bay of
Bengal/Andaman sea
Figure 4 shows the result of mapping the routes described on Sukhothai stone inscription
No.11 into the GIS. Ishii concludes that the four routes shown in Figure 4 existed from the
Sukhothai dynasty to the early part of the Ayutthaya dynasty((1) Martaban—Moulmein—
Mae Sot—Sukhothai, (2) Dawei (Tavoy)—Bon Ti—Kanchanaburi, (3) Myeik (Mergui)—
Tenasserim—Dan Sing Khon—Prachuap Khiri Kan—Phetchaburi, (4) Phuket—Nakhon Si
Thammarat).
(1) Myanmar-Thailand border
(2) Sangklaburi immigration office
(taken from the Thailand side)
at Thai border post
Figure 5. Likely border crossing point for Route 2, one of the 4 trade routes
[Photos taken by author on August 28, 2012.]
In fact, surveys of historical sites by the Fine Arts Department, Ministry of Culture,
Thailand have discovered Khmer-style sites and artifacts at Si Thep, located between
Phetchaburi, Suphan Buri, Ayutthaya, and Phitsanulok, so it is known that there was a
trade route. In Figure 5, the second route from the top is a corridor running on the Thailand
side from Lopburi, Suphan Buri, and Kanchanaburi to Myanmar. Figure 5 shows photos
taken by the author at the border crossing on this route.
1-2. Royal Road runs in three directions from Angkor
Returning to the situation in the Angkor period set out in Figure 2, archaeologists have been
researching the Royal Road for over a century. Evidence for the route includes the Preah
3
In Search of East-west Corridor towards New Horizons on GIS-Based Informatics for ANGIS Paper: 2012/12/1
Khan stone inscription (1191.A.D.), 121 dharamshalas (rest house chapels) 15 rest houses,
and 102 dispensaries. Recently, the Living Angkor Road Project1 (LARP project) has
researched the road from Angkor to Phimai in Thailand, discovering and surveying villages
located several hundred meters away from the main route that were involved in the
production of steel, salt, or laterite. The Royal Road can be described as having three
principal routes: (1) A route from Angkor to Aranyaprathet in Thailand, (2) A route from
Angkor to Phimai, and (3) A route from Angkor passing to the south of the well-known
historical site at Preah Vihear, then continuing to Wat Phu in southern Laos.
Figure 5. Royal Road around Angkor
(Source: Bruno Bruguier 2000, BEFEO)
Figure 6. Khmer Empire and Khmer sites
(Red dots and Inside of red poly-line)
Figure 5 shows the routes taken by the Royal Road from Angkor Wat in Cambodia. In Figure
6, the Royal Road is overlaid in the GIS with the locations of approximately 350 Khmer-style
sites. By combining this information, you can see that a large number of Khmer sites are
situated near to the ends of Royal Road Route A and Route B. This map also shows that
there are Khmer-style sites at locations outside the area controlled by the Khmer Empire
based on the map derived from the TimeMap Project. This is new findings on GIS-based
study. The base for this map is a current vector map of the Indochinese peninsula in the GIS.
As described above, the author has added a number of layers to the map to show the extent
of the Khmer Empire using 52 thematic maps showing the extent of rule or control (provided
by Prof. Roland Fletcher of the University of Sydney), a number of examples of the East-West
Corridor based on the Ishii theory, Royal Road Route A according to the Sakurai hypothesis,
Royal Road Route B according to the LARP project, and also the locations of some 350 Khmer
sites. The contemporaneous kingdoms in Myanmar (Burma) are also mapped. Furthermore,
to incorporate information about Hoshino's sema culture[Hoshino 1990], the sema stones
used to mark the boundaries of the space for Theravada Buddhism ordination ceremonies are
also mapped in the GIS.
2. What can be seen from the GIS mapping
The data listed above was insufficient for an investigation of the East-West Corridor
centered on Thailand. As a subsequent step, the author took the data on about 800
historical sites in Thailand obtained from the LARP project and entered it into the GIS.
It must be remembered that since the GIS handles spatial data, the process of
incorporating information into the GIS requires clear latitude/longitude data for each
item before it can be mapped and incorporated into the GIS map. The latitude/longitude
data was added to data for the four routes between Myanmar and Thailand listed in the
context of the East-West Corridor, the three routes from the findings of Royal Road
research, and also for approximately 350 Khmer sites, and approximately 800 sites
within Thailand. Latitude/longitude data was also clarified for all the 52 maps showing
power relationships in the Indochinese peninsula.
4
In Search of East-west Corridor towards New Horizons on GIS-Based Informatics for ANGIS Paper: 2012/12/1
The point data for these maps and historical sites, and the line data showing the
East-West Corridor was all layered onto the base map. The result, omitting only the
sema culture information, is shown in Figure 7.
Figure 7. Information on the East-West Corridor, Royal Road, Khmer sites,
sites within Thailand, and Burmese kingdoms layered onto a map
of power relationships of the Khmer Empire
Having mapped all this information into the GIS, the next step is to examine what emerges.
(1) The form of the East-West Corridor emerged along with the rule and control of the Mons
and Khmers, and with the rise and fall of the Sukhothai Kingdom and Ayutthaya Kingdom.
In particular, the East-West Corridor emerged strongly with the rise of the Sukhothai
Kingdom. In contrast, when the arrangements and forms of sites in the preceding Angkor
period are mapped in time and space, contemporaneous trade routes from the Royal Road to
the regions emerge. Conventionally, researchers have to take the various phenomena
emerging from historical descriptions and bring them together in their own minds to sort out
and evaluate the information. That process was not always accurate, and was prone to
omitting or not noticing information. Currently, research in collaboration with Thai
researchers is in progress to investigate predominantly the routes for the Khmer sites. From
the mapping achieved to date, the routes emerging are much like those shown in Figure 7.
The East-West Corridor shown in Figure 8 depicts nearly all the main routes and regional
routes for communication and trade from the 11th century to the 14th century. Note,
however, that the different routes actually existed at different times, so further analysis
incorporating a time axis is still required.
Recent surveys by the Fine Arts Department, Thailand have shown that the route
from Petchabun to Sri Thep in Figure 8 (center of Figure 8) was actually a river route using
the Pasak River, and there is not yet sufficient evidence to confirm the route from Phimai to
Chaiyaphum and Sri Thep. That confirmation will have to wait for subsequent surveys.
5
In Search of East-west Corridor towards New Horizons on GIS-Based Informatics for ANGIS Paper: 2012/12/1
Figure 8. The East-West Corridor that emerged in the GIS
(2) The locations of the Khmer-style sites extend further than the rule and control of the
Khmer Empire in the Indochinese peninsula power relationships map where the empire
controls the largest area (the map for 1181-1219). Wat Phra Si Rattana Mahathat in Si
Satchanalai, Sukhothai Province (in reign of Jayavalman VII, 1181-1219.A.D.) is a
representative example. This observation has to be interpreted as indicating that the
Indochinese peninsula power relationships maps have been drawn in the basis of reference
materials, and the areas depicted in the maps have been determined with reference to
today's national boundaries, but that the results are inconsistent with reality. In fact,
controlling power does not extend uniformly over an area. In contrast, the proper way to
determine the extent of such relationships is probably to consider routes based on
topography and environment, since it is features such as roads, rivers, and the presence of
local villages that determine how easily ethnic groups can move.
Figure 9. Si Thep Khmer-style sites
Figure 10. Kanchanaburi Khmer-style site
Wat Prasat Mueang Sing
(Photo taken by author on August 29, 2012)
6
In Search of East-west Corridor towards New Horizons on GIS-Based Informatics for ANGIS Paper: 2012/12/1
(3) A new hypothesis emerges: A route from Sri Thep to Lopburi, Suphan Buri, and close to
Ayutthaya has made a very large contribution to trade. In particular, there are Khmer-style
sites from Phetchaburi (near the resort of Hua Hin) to Suphan Buri, Lopburi, and
Kanchanaburi, and there is evidence to demonstrate such a route, but it is very interesting to
note how the routes have changed over time. Also, these areas all have major river systems,
and manufacturing sites for Thai ceramics are distributed throughout the same areas.
(1) Aerial photograph taken in 1945 (WHC2)
(2) Wat Phra Si Ratthana Maha That
(Photo taken by author on October 4, 2012)
Figure 11. Khmer-style site in Lop Buri
Figure 9 shows a Khmer style site at Si Thep, and Mon sites are visible only a few hundred
meters away. Figure 10 is on the route from Dawei (Tavoy) in Myanmar to Kanchanaburi
that is linked to the border crossing point shown in Figure 5. Figure 11 shows that this
prospered as part of the Dvaravati kingdom from the 6th century to the 11th century. It is an
extremely important location when considering trade routes.
3. Conclusion
With focusing on western part from the Chao Phraya river as the author has stated before,
the East-West Corridor to the west of the Chao Phraya river system in Thailand can be
considered that it appears to have a very strong relationship with Khmer-style sites. The
reason for that conclusion is that, as described above, the extent of Khmer rule and control
appears to be related to the ease of access via roads, rivers, and other features. In terms of
historical periods, the area around Lop Buri was one of key locations in the early Angkor
period when the Dvaravati principalities were overcome from the 9th century to the 11th
century. Also, in most northern part in Thailand, Wat Chao Chan can be considered as a
Khmer-style site behind Wat Phra Si Ratthana Maha That Chaliang, Si Satchanalai,
Sukhothai province located. Afterwards, Khmer-style architecture increases from the 12th
century to the 13th century, and since were at key locations for the East-West Corridor, they
surely also functioned as landmarks. These strategic locations continued might be considered
as political, cultural, and economic trading routes around the Chao Phraya river system in
the subsequent Sukhothai dynasty and Ayutthaya dynasty.
The points set out above are the main points discovered through mapping in the GIS.
For the 350 Khmer sites and around 800 archaeological sites with adding other resources
within Thailand, further work is required to conduct analysis on a time axis as done for the
Maritime Asia network, and in conjunction, to perform spatial mapping for these items. In
order to carried out these studies, collaborations between Thailand, Cambodia, and other
related scholars must be needed and most important way of studying.
7
In Search of East-west Corridor towards New Horizons on GIS-Based Informatics for ANGIS Paper: 2012/12/1
Notes
1. LARP: Living Ancient Road from Angkor to Phimai Project. This project to research the Thailand Royal
Road was conducted from 2004 to 2009 in collaboration with Cambodia APSARA (Authority for the
Protection and Management of Angkor and the Region of Siem Reap), with funding from the Thailand
Research Fund. Project leader was Dr. Surat Lertlum (Chulachom Krao Royal Military Academy).
2. WHC: Williams-Hunt Collection. Collection of aerial photographs of Indochina and Southeast Asian
islands taken by Peter Williams-Hunt (U.K.) over several years beginning in 1944. The collection is
currently housed in locations that include SOAS at London University, the Center for Southeast Asian
Studies, Kyoto University (CSEAS), and Singapore. CSEAS holds approximately 5,000 photographs from the
collection.
References
[1] Shibayama, Mamoru. 2012a. "Chiiki joho mappinngu kara yomu tonan Ajia" (Reading Southeast Asia
from Area Information Mapping), Bensei.
[2] Shibayama, Mamoru. 2012b. "In Search of East-West Corridor by Japanese Scholars: Geoinformatics and
Cultural Regions," Workshop on Studies along the East-West Cultural Corridor, Field School of Archaeology
(FSA), Pyay, Myanmar, 21st August.
[3] Kakizaki, Ichiro. 2011. “Tonan Ajia wo manabou” (Let’s learn Southeast Asia), Chikuma.
[4] Ishii, Yoneo. "Tonan Asia shi no teisetsu wo saikento suru" (Re-examining established theory in
Southeast Asian history), Japan Society for Southeast Asian Archeology Monograph No.4, Japan Society for
Southeast Asian Archaeology, pp.1-7, 2006.
[5] Ishii, Yoneo. 2008. "History and Environment," Handout in Workshop on Area Informatics, Center for
Southeast Asian Studies, Kyoto University.
[6] Ishii, Yoneo. 2009. "Sukhothai wo tsuka suru 'tozai kairo' ni kansuru oboegaki" (A note on the East-West
corridor passing through Sukhothai), published in Tonan Asia: Rekishito Bunka (Southeast Asia: History
and Culture), No.38, pp.5-12.
[7] TimeMap Project. 2003. “Animated TimeMap of the Khmer Empire 100 CE - 1550 CE”, University of
Sydney, Australia. http://www.timemap.net/.
[8] Khmersearch. http:// www.panoramio.com/user/1549852.
[9] Ishii, Yoneo. 1991. "Six Hundred Years of Thai-Japan Relationship" in Tai kinseishi kenkyuu josetsu
(Collected Papers on the Early Modern History of Siam), Iwanami Shoten, pp.48-66.
[10] Ishii, Yoneo and Toshiharu Yoshikawa. 1987. "Six Hundred Years of Thai-Japan Relationship,"
Kodansha.
[11] Sakurai, Yumio. 2012. "Histoire de La Voie Royale Angkorienne," Handout in Seminar at Kyoto
University Center for Southeast Asian Studies Bangkok Liaison Office, June.
[12] Hoshino, Tatsuo. 1990. "Dakuryu to mangetsu: Tai minzokushi e no shotai" (Muddy Stream and Full
Moon: Invitation to the History of Ethnic Groups in Thailand), Kobundo.
(28
8
th
November 2012)