IV. Conditions Prior to the 6th Century
The portion of the Enoshima Engi translated in this part of the
study describes conditions around Enoshima before 552 AD (the date
assigned by Kokei to the descent of the goddess Benzaiten onto
Enoshima). So let us see what modern historians tell us about the
conditions prevailing in this area prior to the 6th century.
First of all, where did the inhabitants live?
A. Location of Settlements
The History of Fujisawa City
underscores the importance of water in the lives of the early
inhabitants:
Let us look into the geological
conditions of the 204 [archaeological] sites mentioned in the preceding
paragraphs. Remains from the pre-earthenware period to the Kofun age
are
generally found distributed along the catchment basins of rivers. The
Sagamihara highland stretches from north to south around Fujisawa City.
The flow of the Sakai River and its tributaries, including the
Shirahata
River and the Hikiji River, has carved deep valleys into the highland.
Archaeological sites are concentrated along the edges of the highlands
that face the drowned valleys (ria). In addition, most sites are found
at locations with spring water directly under the highlands. This
testifies to the deep connection between water and human life (
History of
Fujisawa City, pg. 21-22).
Shunno Ohashi, the author of the History
of Totsuka City (戸塚の歴史),
provides
details on how the villages in the area were formed.
Villages would have gradually formed
around the inlets to the deep valleys that were formed in this way [by
the Jomon Transgression]. This we know because remains from both Jomon
and Yayoi cultural periods are found on the highlands, on the hills
between flowing rivers. These meandering, swelling rivers must have
flooded repeatedly, causing problems to many of the inhabitants. From
experience and knowledge, they avoided the floodplains of the Sakai,
Kashio, and Itachi Rivers; instead they sought secure habitation on
high
terraces. In this way, villages grew up along hills (
戸塚の歴史, pg. 14-15) (1).
Archaeological investigations have pin-pointed the location of
settlements in the area during the Kofun (or
Burial Mound) Era (300-710
AD). Most of this period is thus prior to the 6th century.
Above are maps of the location of these settlements according to History of Kamakura City: Archeology
(鎌倉市史 考古編, pg. 52) and History of Fujisawa City, Archeology (藤沢市史、第４巻, pg. 29). Note that according to
the map at the left, the Tsu valley was relatively heavily populated
while the area around the Ofuna Estuary, which extended almost as far
as
present-day Totsuka City, was not heavily populated. (The map at the
right, published by Fujisawa City, does not extend to cover the Ofuna
Estuary because most of it lay within an area that is under the
jurisdiction of Kamakura at present.)
For further orientation, below is a topographic map of the area created
around 1883 (from 藤沢市：地図に刻まれた歴史と景観, pg.
44) with the locations of relevant landmarks marked. Part of Tsu valley
can be seen at the lower right.
The History of Totsuka City
contains more detailed information on the settlements in the vicinity
of
the Ofuna Estuary during a period it estimates at 1-300 AD. The History states:
Ruins known as "Kango" [a settlement
surrounded by a moat, probably for irrigation and/or defensive
purposes]
that appear to belong to that period have been discovered in Sotogo
[name of a tableland] in Kamikashiocho [a place several kilometers to
the northeast of Totsuka]. The surrounding ring moat is rectangular,
extending 95 meters south to north and 65 meters east to west. The east
and west ditches of the moat run largely straight; however, the west
ditch is bowed slightly inward. It is not clear when this site was
initially settled; however, it appears to have been in the Middle Yayoi
Miyanodai sub-period [around 1 AD by the estimated chronology on pg. 27
of the History]. Here and there, ranging from the early part of the
Late
Yayoi (Kugahara pottery) to the middle and later parts of the period,
are the remains of habitations that appear to have been built over
earlier remains up to eight times. It appears that the habitations were
built, then destroyed, and then rebuilt again and again. The ditch
around the settlement is a surrounding ring moat, dug in a "V" shape
with a width of about 2.5 meters.... The settlements on the Sotogo
[tableland] are located at elevations of 40-50 meters above sea-level.
The paddy rice fields used for food production were at the foot of the
tableland. (
戸塚の歴史, pg. 29-30) (2)
Although Ohashi does not state directly what destroyed the habitations,
he implies that the destruction was caused by earthquakes (see the following passage below).
Summary
Firstly, most of the settlements were located in the Tsu valley. If our
tentative identification of Tsumura as being in the Tsu valley is
correct, then the settlements were located precisely where the Enoshima Engi places the villages.
Secondly, the inhabitants of the Ofuna Estuary (which later became the
floodplain of the Kashio River) lived in an area subject to frequent
flooding and earthquakes, which often destroyed their dwellings.
B. The Origin of the Long, Swampy Lake
The lake may well have had a sudden origin around 100 AD, according to
the History of Totsuka City,
which states:
[The
noted archaeologist Dr.] Naotada Akaboshi, who studied erosion in
caves,
found that the bottoms of the erosion-generated caves were
approximately
5 meters above sea-level at the south of the Miura peninsula [the
peninsula between Sagami Bay and Tokyo Bay] and 3 meters above
sea-level
at Sarushima Island [an uninhabited island in Tokyo Bay near Yokosuka].
From his findings, he deduced that an earthquake had taken place,
resulting in a crustal uplift of about 3 meters above sea-level. As a
result, the seawater of the Ofuna Estuary, which had deeply invaded the
land, suddenly withdrew. The area that had been covered by seawater
became an alluvial mudflat with swamps here and there. The place-name
"Wada," which is found as part of the names of places in Totsuka and
Hongo, is derived from "Wadatsumi," which is a reference to the "sea"
and the spirit of the sea. As such, "Wada" in place-names may be
regarded as a legacy indicating the former presence of the sea. The
place-name "Naganuma" ["long swamp"] refers to a place left behind
after
the retreat of the sea; it appears to refer to a topographical feature
that had become a swamp. It also appears that sea-level at that time
was
about 3 meters higher than the present shoreline (
戸塚の歴史, pg. 26) (3).
The History also attempts to
date the earthquake:
The major earthquakes that jolted the
land, causing uplift, took place in the Kugahara sub-period [100-300 AD
by the estimated chronology on pg. 27 of the
History] (
戸塚の歴史, pg. 29-30) (4).
Summary
Whether or not the date is correct, the above references contain
several important points: there is geological evidence of the "long,
swampy lake" mentioned by Kokei in the Enoshima
Engi; the transition from estuary to swampy lake was caused by
an earthquake, and as such it was sudden, not gradual; and the early
inhabitants lived high on the terraces of hills to avoid floods.
The references also suggest an answer to the question of what the lake
was and where it came from. A glance at this map of
Jomon-era sites shows two long estuaries: the Ofuna Estuary and the
Fujisawa Estuary to its left. Either could have been the precursor of
the long, large, swampy lake mentioned by Kokei in the Enoshima Engi. There are, however,
two reasons why the Ofuna Estuary is the most likely candidate.
Firstly, the references by Ohashi state
specifically
that the Ofuna Estuary underwent a sudden transition from estuary to
mudflat and wetland. (When flooded, it would have been a lake.)
Secondly, Kokei mentions that the lake was vast. The Ofuna Estuary was
the largest of the two. See also this
section.
C. The Flooding Problem as Described by Kokei
The picture of conditions painted above by Shunno Ohashi, the author of
the History of Totsuka City, is remarkably consistent with the picture
depicted by Kokei in the Enoshima
Engi,
if we assume that the dragon represented water (flood waters, in this
case).
The Chinese version of the Enoshima
Engi states that the dragon began its rampage in the ancient
past
in the following manner:
... the evil dragon, accompanied by the
spirit of the wind, demons, mountain spirits, and other spirits,
wreaked
calamities throughout the land. Mountains and hills crumbled, releasing
floods and causing damage resulting in plagues and revolts.
The following episodes apparently took place just prior to 552 AD:
Before the valley lived a village
elder. He had 16 children, all of whom were swallowed by the poisonous
dragon ["poisonous dragon" is a stock phrase meaning "evil dragon"].
Grieving and anguishing, he left his old home to move to a location to
the west, which was then called "Elder's Mound."
As can be seen from this map of
Kofun-era sites, there are not many burial mounds in the vicinity of
where Tsumura was located; however, there are two burial mounds to the
northwest. One of these may be the mound referred to in the Enoshima Engi.
The following passage states:
The evil dragon then spread out through
the villages, swallowing and devouring children. Terrified, the
villagers forsook their homes to move elsewhere. The people of that
time
named the new location Koshigoe.
If the dragon represented flood waters, that suggests a reason why the
villagers fled and why they chose Koshigoe to flee to. It could have
been because their village, Tsumura, was located in a valley in the
side
of South Hill (present-day Katase Hill). Koshigoe lies on higher ground
just to the west of Tsumura (6). If our interpretation of the nature of
the dragon is correct, then the inhabitants were probably fleeing water
that was flooding their village. Perhaps the flood waters were rising
quickly, as the waters swallowed children and terrified the
inhabitants.
See The
Relationship between the Puyang River in China and the Kashio
River. This section points out similarities between the
Kashio River and the Puyang River south of Hangzhou, China. The Puyang
River frequently experienced heavy rains in its hilly catchment area,
swelling the river. The heavy volume of water speeding down its channel
would rush up against the incoming tide, causing serious flooding. A
similar situation may have existed around the Kashio River, resulting
in rapid flooding that forced the inhabitants to flee. 
(This paragraph was added in February 2006.)
Tombs Dug into the Sides of Hills
A type of stone tomb carved into the side of a hill was widespread
during the Kofun era. Known as yokoana
(横穴), or "horizontal hole," they were especially common on Katase Hill
along the left bank of the Katase (Sakai) River, running from
Dragon's-Mouth Temple to Kawana in Fujisawa City, and along the Kashio
River. This is more or less the area in which the action of the Enoshima Engi took place. There are
18 clusters of such tombs in this area, amounting to 125 tombs in all
according to History of Fujisawa City,Archeology ((藤沢市史、第 ４巻,
pgs. 265-266).
Above is a photograph of a cluster of such tombs on an island in the
flood plain of the Kashio River (ふじさわ,
pg. 27). These tombs fit the description of the caverns in which people
were forced to take refuge from the "rains of fire" (or "heavy rains,"
by another interpretation) mentioned here in the Enoshima Engi.
Of course, the cave-tombs are anachronistic because they date from a
later period. However, if Kokei wrote based on information about
Enoshima brought back by monks who had visited the area, he probably
only knew that yokoana tombs
were common, not that they dated from a later period.
It is now possible to compile a
partial list of details in Kokei's description that have been supported
by various kinds of evidence. Refer here
for the list.
Summary
Kokei's description is fairly consistent with the picture of the area
based on the results of archaeological and geological studies. The
villagers of Tsumura appear to have been living in a valley in a hill
on
the coastline. The primary candidate for the cause of the flooding is
the passage of a tropical storm that dropped a great deal of rain
inland coupled with an incoming tide (see the discussion
of such a situation at the Puyang River in China), resulting in a flood
in the floodplain of the Kashio River, and
an accompanying storm surge causing an additional rise in waters in the
estuary on top of the incoming tide. At
present, tropical storms pass through the area several times per year.
The passage of a storm accompanied by an
incoming tide and a storm
surge could
have
produced serious flooding, causing the inhabitants to flee.
Go to V. Summary and Conclusions
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(1) Japanese text of citation translated above (戸塚の歴史, pg. 14-15)
(2) Japanese text of citation
translated above (戸塚の歴史, pg. 29-30)
(3) Japanese text of citation
translated above (戸塚の歴史, pg. 26)
(4) Japanese text of citation
translated above (戸塚の歴史, pg. 30)
(5) Also see 沖積平野 (Alluvial Plains),
which devotes an entire chapter to the minor rise in sea-level
(amounting to 2-3 meters) from the 4th through 12th centuries (沖積平野, pgs 107-114).
(6) Some maps show a second section of Koshigoe on higher ground to the
east of where Tsumura was located. This area is so steep that it has
not
yet been made into a residential district. However, whichever side of
Tsumura the villagers fled to, they probably fled to nearby higher
ground.
