A Missing Link: Transfer of Hydraulic Civilization from Sri Lanka to Japan
ABSTRACT Sri Lanka has the highly developed hydraulic engineering heritage in the shape of reservoir tanks and several derivatives of water channels still being used today in order to accommodate water and soil conservation ecosystem from ancient times. In Japan at relatively drier areas corresponding reservoir tank structures were also built in ancient times and have been maintained over the centuries. One notable example of such tank, named Mannou-Ike, exists in Kagawa Prefecture near the Inland Sea of Seto, which was completed in the early 9th century in the similar design as that of Sri Lanka under the command of an eminent Buddhist monk, Ku-Kai, who once was sent as a student to China where he mainly studied Buddhism, esoteric practices, also scientific knowledge and presumably civil engineering as well. He might bring such knowledge and technology back to Japan and might apply such skills in Mannou-Ike works. What this paper argues is still one conjecture but creates sound and good imagination of important relationship in terms of technological transfers from Sri Lanka to Japan via China. This author believes that there are plenty of circumstantial evidences but yet exists solid evidence to support this conjecture. However this area of studies is very much worth trying and investigating, then establishing the proof in order to connect this missing link of civilizations.
Pugwash Regional Workshop
Learning from Ancient Hydraulic Civilizations to Combat Climate Change
Colombo, Sri Lanka, 22-28 November 2007,
A Missing Link: A Missing Link:
Transfer of Hydraulic Civilizations from Sri Lanka to Japan Transfer of Hydraulic Civilizations from Sri Lanka to Japan
Sri Lanka has a highly developed hydraulic engineering heritage in the shape of
reservoir tanks and several derivatives of water channels still being used today in order
to accommodate water and soil conservation ecosystem from ancient times. In Japan at
relatively drier area corresponding reservoir tank structures were also built in ancient
times and have been maintained over the centuries. One notable example of such tank
named Mannou-Ike, exists in Kagawa Prefecture near the Inland Sea of Seto, which
was first built in the early eighth century, then restored in the ninth century in the
similar design as that of Sri Lanka under the command of an eminent Buddhist monk,
Kukai, who once was sent as a student to China where he mainly studied Buddhism,
esoteric doctrine, also scientific knowledge and presumably civil engineering as well. He
might bring such knowledge and technology back to Japan and might apply such skills
to Mannou-Ike restoring works.
As far as ancient documents tell us that interchange of knowledge and information
took place between Sri Lanka and China, particularly visits of Chinese Buddhist monks
to Sri Lanka for the purpose of studying the authentic Theravada Buddhism. One
representative figure was Fa-Hsien who traveled to Sri Lanka in the early fifth century.
One can fairly expect that those monks not only studied Buddhism but also science and
technology either indigenously developed in Sri Lanka or imported from India or the
Middle East and then brought them back to China.
This article is still one conjecture but the author contemplates that this discussion
creates sound and good imagination of important relationship between countries in
∗ President of Keio Academic Enterprise Co Ltd, an affiliate of Keio University in Japan and
Former Director of Research Institute of Capital Formation, Development Bank of Japan.
Also a member of the International Association for the Study of The Commons.
terms of mainly technological transfers but also socio-cultural implications.
Main features of the ancient Sri Lankan irrigation system Main features of the ancient Sri Lankan irrigation system
In the survey of world civilizations, Arnold Toynbee described the ancient irrigation
system of Sri Lanka as an amazing system of waterworks where hill stream were
tapped and their water guided into giant storage tanks from which ran channels into
other large tanks. Below each tank were hundreds of little tanks. The irrigation system
has been sustained since before the third century BC.1
The reason why this peculiar system evolves is partly the climate and the geography.
The south-west of Sri Lanka has ample water and is known as the ‘wet-zone’. The rest of
the island is referred to as the ‘dry-zone’. Intercepting these zones is a mountainous
region form which rivers flow out. The ‘dry-zone’ is prone to droughts, and irrigation
works to regulate, transport, and conserve water are essential to support agriculture.
Until the eleventh century large-scale irrigation networks of reservoirs and canals
with over 20,000 village tanks, and a compatible social system with such environment
evolved. In Sri Lanka successive kings and monarchs unmistakenly took the initiative
of supervising the construction of massive tanks and canals. The purpose and
conviction of building the irrigation systems are depicted by the words of King
Parakrama Baru (1153–1186 AD): "Let not even a small quantity of water obtained by
the rain, go to the sea, without benefiting man".2
Karl Wittfogel argued that the political economy of oriental hydraulic societies
engendered centralization of power in a despot, with bureaucracy and unpaid labour.
Such despotism is unlikely to have sustained the irrigation system for long as the
political system is overly dependent on the sagacity and skills of the rulers.3 Contrary to
Wittfogel’s contentions, Edmund Leach showed that the villages in Sri Lanka were
highly decentralised in a manner that was the very antithesis of the state control.4 This
aspect of hydraulic civilisation in Sri Lanka is very unique.
Regarding technology used for irrigation system in Sri Lanka hydraulic control
through weirs, anicuts, sluices and valve pits testifies to indigenous technological
expertise. The valve pit or bisokotuwa is a pivotal invention in the construction of tanks.
There is evidence for substantial indigenous innovation and skill in the construction of
1 Toynbee (1934) [vol.1]: p81. Major irrigation schemes date back to the fourth to the third
century BC, as evident from the earliest written records in the Mahavamsa (Seneviratna
2 Brohier (1934) [vol.1]: p5.
3 Wittfogel (1957).
4 Leach (1959).
irrigation works. Yoda-Ela canal, which is over 54 miles long, has one stretch of over 17
miles with an altitude difference of only 6 inches, such an astonishingly easy gradient,
testifying to sophisticated surveying skill.5
The village tanks along with the ancient large-scale irrigation works are a salient
legacy that has sustained inhabitants over many centuries. However this ancient
irrigation system reached its peak in the north-centre of the island: in Anuradhapura in
the tenth century and in neighbouring Polonnaruwa in the eleventh century. Although
the aftermath of Sri Lanka’s hydraulic society under the colonial rule and the
post-independence regime is very important to pursue and interesting, so far we would
like to ascertain that such great hydraulic civilization was evolving in Sri Lanka in the
relevant period when Chinese and Japanese monks encountered Indo-Sri Lankan
civilizations over Buddhism.
Travel of ideas Travel of ideas
Along so-called ‘the Silk Road’ an extensive interconnected network of trade routes had
been developed across the Asian continent connecting East, South and Western Asia
with the Mediterranean world, including North Africa and Europe. The Silk Road was
not only conduits for silk, but for many other products and was also very important
paths for cultural and technological transmission by linking traders,
merchants, pilgrims, monks, soldiers, nomads and urban dwellers from China to the
west or the other way round for thousands of years. Europeans in the medieval period
saw major technological advances taken place in China, such as movable
type printing, gunpowder, the astrolabe, and the compass. Also the sea-routes via
Southeast Asia, India, and the Muslim world were developed for merchants and
vinaya7 in India. One can fairly expect that those monks not only studied Buddhism but
Regarding Sri Lanka, India, and China, according to the ancient documents the
transfer/interchange of knowledge and information took place fairly constantly,
particularly through visits of Chinese Buddhist monks to Sri Lanka for the purpose of
studying authentic theravada Buddhism. (See the attached Figure 1). One
representative figure was Fa-Hsien6 who traveled to Sri Lanka in the early fifth
century extending his journey in search of Buddhist texts particularly those of the
5 Brohier (1935) [vol.2]: p8, Mendis (1999) pp164-166.
6 Chinese Buddhist monk born in 337 AD, died in 442, travelled for India and Sri Lanka
between 399 and 414. In Sri Lanka he stayed for 2 years ( 411 to 412) mainly in
7 A word in Pali
(literally leading out, education, discipline) means the regulatory
also science and technology either indigenously developed in Sri Lanka or imported
from India or Middle East and then brought them back to China. However what we
miss in Fa-Hsien’s book of travel is that although he mentioned prosperity (including
jewels and pearls) and the beauty of Anuradhapura and environs, and the flourishing
monasteries, he did not leave the descriptions of landscapes, tanks (no mention about
the huge Tissa Wewa! ), and streams of the country in his book of travel.
After Fa-Hsien several Chinese monks visited India to get access to Buddhism.
Representative people were Hui-Seng and Sung Yun stayed India from 518 to 522, and
the greatest of all the Buddhist pilgrim-scholar-diplomats was Hsuan-Tsang (or
Xuanzang), who was in India between 629 and 645. The fifth important name is I-Ching,
studying and travelling in India between 671 and 695. There was little evidence but
other monks might visit Sri Lanka other than Fa-Hsien.
On the other way round Kumarajiva, a monk, whose father was an Indian visited
China in 386 to powerfully propagate Mahayanist doctrine. Again Amoghavajra whose
father was a Brahmin from North India went to Sri Lanka then to China and taught
Buddhism. His disciple Huiguo eventually taught Kukai early ninth century in
Chang’an, the Tang capital city. There were also many embassies from Sri Lanka during
the fifth century. The interval between the fourth to the end of the seventh century may
be the great Chinese-Indian-Sri Lankan period.
Rice cultivation and China Rice cultivation and China
Although the dryland cultivation of rice went back to 8,000 to 10,000 years ago in China,
the wetland cultivation started at the latest 5,000 to 7,000 years ago. According to A. L.
Buck, an American agronomist, Chinese arable part of the whole country could be
divided into 9 agricultural areas: 1) Maize-millet-soybean area, 2) Spring wheat area, 3)
Winter wheat-millet area, 4) Winter wheat-sorghum area, 5) Yangtze rice-wheat area, 6)
Rice-tea area, 7) Szechwan rice area, 8) Double-cropping rice area, 9) Southwestern rice
area.8 People grow rice in five areas out of nine. In China the distinction between the
rice-growing south and the wheat-or-millet growing north is fundamental and enduring.
Therefore the irrigation matters when the wet-rice cultivation is concerned.9 Wet-rice
cultivation is staple in the south of the line drawing between the north part of Szechwan
basin and the north part of Yantze River.
In terms of technical concept ‘water control’ covers three interlinked categories:
framework for the Buddhist monastic community based on the canonical text book called
8 Buck (1937), See Figure 2.
9 See Figure 3.
irrigation, drainage, and flood control. Irrigation, the supplementing of an insufficient
water supply, may be carried out on almost any scale from the individual household to a
whole province or nation. Drainage, the removal of excess water, tends to require
greater investments of labour and other resources, and cannot usually be carried out
without the cooperation of a relatively large community. Flood control along the great
rivers requires enormous investments in construction and maintenance, but since it is
literally a matter of life and death for thousands if not millions of their subjects, and
often a matter of national survival as well. Chinese monarchs have made it a primary
found in the Yangtze river-basin and much in the
outh and southwest of the country.
e increasingly common. The proportion of land
10 Because the flood control of the Yellow River was crucially important, historically great
river improvement and canal works have been undertaken by centralized powers in China.
11 The word means a large tomb of local lords and monarchs. Its building technology. The
period attached this word represents a piece of time period in history when many tombs of
Kofun are excavated later.
12 Gyoki thought to be a decendant of immigrants from Baekje in the Korean Peninsular.
People emigrated from the Korean Peninsular and China, mostly technicians and
professionals in several disciplines, contributed to Japanese technology and culture in those
days. Particularly after the collapse of Baekje in the late 7th century many escaped from the
country and immigrated into Japan.
concern since very early times.10
Typical irrigation methods of which are utilized in the wet rice cultivation areas are:
1) gravity-fed irrigation networks, 2) ponds, tanks, and reservoirs, 3) contour canals, 4)
creek irrigation. All four types are quite prevalent at rice paddy fields in China. If there
was a possibility to have information exchanges on construction works and
management of water control, we presume technology transfer of these methods of
irrigation including tank related techniques. Historically the irrigation facilities using
reservoirs and village tanks can be
Irrigation works in Japan Irrigation works in Japan
Tanks and small reservoirs are the most ancient type of irrigation supply in Japan.
They were probably introduced from Korea in about the fifth century AD. We call this
span of time ‘Kofun’11 period (the third to sixth centuries AD) in Japan. Many smaller
tanks are identified as built in this period archeologically. Also technological base for
building Kofun and the tank is said to be shared. Later in this country as feudal warrior
class started building up their local bases and expanding the area of cultivated land
under their control at least after the tenth century, larger irrigation networks based on
small rivers and derivation canals becam
Japan irrigated by tanks fell steadily.
Before focusing Kukai’s works we should mention Gyouki12 (668 - 749) as his great
predecessor of irrigation works. Gyouki was also a Buddhist monk and during his
earlier days formed a strong religious group to help the poor. Because of its
revolutionary nature the group was oppressed by the government. However, he was
recognized later and became positioned as a higher rank in the main Buddhist order. At
the same time he directed in constructing and restoring several irrigation works in
Osaka area, of which Sayama-Ike is the most notable one, carried out in 731. In the
process of excavation during recent restoration13 of this reservoir many findings
revealed how the inner structure of the bund, sluice, and spillways etc are. One feature
to be noted is the way of using grasses and shrubs as reinforcing material for the bund
building. Such adopted technique is also identified in some Chinese14 and Korean15
ases in the field.
us. After coming home he eventually became involved this
13 The restoration and excavation work were carried out from 1989 until 2002.
14 Later Han dynasty (the 1st to the 3rd century)
15 In the 4th century.
16 The annual precipitation in this area is 1,123mm (at Takamatsu, cetre of this area, the
annual average amount between 1971-2000). National Astronomical Observatory (2008).
Kukai and Mannou-Ike works Kukai and Mannou-Ike works
Along the progress of irrigation development in Japan we propose a symbolic example of
the works involving one eminent Buddhist monk, Kukai (774-835) (See Figure 4). He
was born in Zentsu-ji, in Sanuki (the present Kagawa Prefecture in Shikoku Island. See
Figure 5.) where this irrigation works is located. At the age of 31 He was sent to China
(in the Thang Dynasty) as a student studying Buddhism, particularly esoteric (later
tantrism) doctrines. Perhaps because he had accomplished the main subject, Buddhism,
he presumed to have studied other scientific disciplines including civil engineering in a
relatively short two-year stay in China. Amongst Japanese historical figures Kukai
thought to be a real geni
eful irrigation project..
Sanuki area has a comparatively drier climate even in the rainy season and few
affluent rivers.16 Plains in the region are little steeper than average and have few
marshes and only rapid streams. Therefore historically tanks and reservoirs were
developed for the irrigation purpose. In Sanuki approximately 16,300 tanks are now
located the most densely in Japan (See Figure 6). Mannou-Ike was built in 702 by the
local governor of Sanuki, which is still the largest irrigation tank (the present water
storing capacity: 15,400 thousand tons) in Japan. In 821, it was heavily destroyed by a
flood and the governor of Sanuki presented the petition to the Imperial Court saying
that Kukai be commissioned as the person responsible for the repair work on the
reservoir. The reason why the governor chose Kukai was that Sanuki was Kukai’s
homebase and he knew that Kukai had been anxious about the rural living conditions
and he had been respected by the native people. The incumbent emperor Saga
appointed him as a superintendend of the restoration work of the reservoir.
technical features17 at the restoration work by Kukai are summarized as
rst designed for reservoir tank systems in Japan.
4.und was made (protecting the bund from pressure at the time
apan. Their estimation of original Kukai’s plan and diagams are very much valuable.)
by or borrowed from the Chinese or imported technology
17 STEC (2000) and Obayashi Corporation (1995).
18 Nagata (2006).
19 Sarton (1927)
1. An arch-shaped bund was fi
2. A spillway was introduced.
3. Renewal of the sluiceway.
A rock bed under the b
f discharging water).
(Regarding these findings we very much owe to the reproduced works carried out by
the staff of Obayashi Corporation, a civil engineering and construction company in
The size and scale of Mannou-Ike (see the Box below) is far greater than other cases
in Japan. Mannou-Ike is four to five times as large as Gyouki’s Sayama-Ike. As far as an
arch-shaped bund is concerned, it is quite unique to adopt such design in the antiquity
and the medieval period throughout the world. Nagata, a Japanese civil engineer,
proposes the supposition that Kukai devised that idea through his observations of many
arch-shaped stone bridges along the travel in China.18 He might apply the principle of
arch using the vertical gravity force to the water pressure to the bund horizontally.
Introduction of the spillway and the rock bed, and improvement of the sluiceway
structure might be influenced
m the other countries.
Later he became a very high priest of Shin-gon School (esoteric doctrine). We should
also mention his another profile. In 828 he started a school named Shugei-Shuchi-In for
the general public (first in Japanese history) in educating not only religion/philosophy
but science, engineering, and other subjects. According to George Sarton19, a
Belgian-American scientific historian, Kukai should be ranked at the first place as a
scientist in the ninth century from the point of human scientific history because of his
contributions to restoring Mannou-Ike in such a technological accomplishment and
creating the school, Shugei-Shuchi-In, based on a creative principle on education.
llowing are the features in Mannou-Ike case. (See also attached Figures 13 and 14)
water21 at the first priority is retained by irrigators with written
n of water resources
. Annual cerebration of the start of discharge of water (June)
20 STEC (2000)
21 Such portion of water is called ‘Shomon-Sui’ (supply of water protected by the deed ) in
est in Japan)
Modern rebuilt: late 19th century and 1959
ox: Mannou-Ike ox: Mannou-Ike (See attached Figur
Size: 138.5ha (the larg
Capacity: 15,400 thousand
First built: late or early 8th
Ku-Kai’s restoration: 821
Restoration in the feudal period: 1631
Water usage: custom and practices Water usage: custom and practices
In Mannou-Ike several rules of usage of water are in practice. In terms of remained
documents we could only track back such custom to the medieval time, but such custom
might have been used at the time of Kukai. As the case like the common resource such
as irrigation water in the reservoir tanks, there are certain specific rules/regulations20
to be observed by stakeholders of the resource in order to preserve such resource. Th
1. Ordering of priority in using water; the crucial rule at the time of draught
2. Right of receiving
3. So-called ‘Incense stick water’: a way of controlling appropriatio
by way of firing time of a stick of incense for each irrigated pad
Such rules/Regulations are quite prevalent in the commons situation in the world.
The commons is a term used in environmental sociology and economics as a type of
resource management system under the communal property regime. In the historical
commons there existed rules which restricted members who had rights of access to the
esource and stipulated/customary regulations of use.22
al landscape that is as functional and
22 Mogi (2008), The commons concept are discussed at this separate article enclosed in this
23 DLO Mendis (1999), p166.
24 Needham et all (1971).
25 Needham et all (1954).
Ending words Ending words
In Sri Lanka village tanks were built and maintained by villagers for keeping their
living complemented by larger irrigation networks including huge reservoir tanks once
built by kings and monarchs in the country. Those systems contributed to keeping
eco-systems of the country far back centuries, being disrupted by the colonial rule but
discovered by the same hand with Sri Lankan collaboration. Today people begin to
reconsider the past development concept and look back the importance of village tanks
and their management, realising eco-friendly undertaking of irrigation systems in
history. According to D.L.O.Mendis, “the Kalaweva-Jayaganga ecosystem”, a
representative socio-hydraulic complex in the country, which houses the Yoda-Ela canal
mentioned earlier, “is a living system, a cultur
ductive as was originally intended.”23
In Japan although the reservoir tank system has relatively smaller role in the
agricultural irrigation from the point of all the country, it has a crucially important role
in drier area in the country. Owing to Kukai’s contributions in the old days Manou-Ike
still works and keeps the traditional custom even if the ownership and control rests in
the public authority, however in cooperation with private farmers at stake. The scale of
Mannou-Ike is exceptional in Japan. Dominant part of irrigation tanks is owned and
managed either by hamlets or mutually agreed cooperatives. Such tanks are often
susceptible to natural decay, earthquakes and others. Proper management is essential
for tanks to be free from disasters like floods. Irrigation tanks cannot be maintai
hout human cares, and such cares are taken by local people in each community.
Dr Joseph Needham, author of Science and Civilization in China, specially
mentioned the development of hydraulic engineering in Sri Lanka from ancient times in
Civil Engineering section of that book.24 At the same time in the introduction volume he
acknowledged the travel of ideas and techniques in terms of Chinese-Indian cultural
and scientific contacts.25 But he reservedly stated just comparison of technological
developments of hydraulic engineering in both countries, and he did not m
luences from Sri Lankan technology towards Chinese one respectively.
However, what we try to do here is to propose one conjecture. Do not these similar
undertakings between countries inspire a sound and good imagination of important
relationship in terms of technological transfers from Sri Lanka to Japan via China? The
author believes that there are plenty of circumstantial evidences but yet exists a solid
proof to support this conjecture. In addition to the researches based on documents, the
comparative civil engineering and archeological approaches might be recommendable.
This area of studies is very much worth trying and investigating, then establishing the
roof in order to connect the missing link of civilizations.
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Science and Technology
Impact to Japan
Map of China’s nine agricultural areas:
showing the division between the northern, dry grain region and the southern, wet-
rice region after Buck (1937)
1: Maize-millet-soybean area
2: Spring wheat area
3: Winter wheat-millet area
4: Winter wheat-sorghum area
5: Yangtze rice-wheat area
6: Rice-tea area
7: Szechwan rice area
8: Double-cropping rice area
9: Southwestern rice area
Source: Needham et all (1971), p11.
Percentage of cultivated land in China under irrigation
Source: Bray (1986), p110. (reproduced from Buck (1937))
Profile of Kukai
The way to the Capital
The Map of Japan
Kagawa Prefecture: Distribution of Reservoirs
Copy right (Obayashi Corporation)
Bird’s eye view on Mannou-Ike
The View from the other side and the arched bund
Copy right (Obayashi Corporation)