2 Japan and the Law of the Sea: Key Historical …
25
area stretches in the area west of the median line to the Okinawa Trough (boat-shaped
basin).
22
China has adopted the natural prolongation theory for the continental shelf and
has claimed that its sovereign right covers the shelf extending to the Okinawa Trough.
Noteworthy is the fact that China operates an offshore platform to fully exploit an oil
and gas field on the Chinese side, about 4.5 km from the median line (the so-called
Chunxiao gas field problem). In contrast, Japan has claimed that the Okinawa Trough
is just a dent, and does not represent any physical limit of the continental shelf, and
that the median line between the two States should be the basis for delimiting their
boundary in the East China Sea that is less than 400 nautical miles wide between
them. This means that Japan sees an overlap of the Japanese and Chinese 200 nautical
mile EEZs as being in dispute, and views the median line as a provisional boundary
for a transitional period until the two States delimit a final boundary by agreement.
Japan has adopted the position that it will maintain its title under international law
to its EEZ or continental shelf extending up to 200 nautical miles from its baseline
until a bilateral boundary is delimited by agreement.
23 This position could be taken
as affecting the significance of the median line as provided by the Japanese domestic
Law on the Exclusive Economic Zones and the Continental Shelf. As for this point,
Japan has explained that its law unilaterally sets Japan’s law enforcement limits and
does not affect its external position.
UNCLOS does not necessarily require any single boundary covering both the
EEZ and continental shelf. This is because the legal title to the EEZ is based on the
standard distance of 200 nautical miles, while the title to the continental shelf depends
on the continuity or natural prolongation of the onshore geological structure (Articles
57 and 76 of UNCLOS). In fact, the continental shelf is characteristically different
to the EEZ. The continental shelf belongs to coastal States ipso facto and ab initio,
and the legal title to the shelf does not depend on effective or nominal occupancy,
or explicit declarations. In contrast, explicit acts are required for establishing the
EEZ. In waters where the EEZ is established, the continental shelf extending up to
200 nautical miles from the coastline is covered by the EEZ. Only any continental
shelf portion beyond the EEZ boundary is related to the natural prolongation theory.
For these reasons, States have tended to delimit common boundaries for EEZs and
continental shelves. In the case concerning the Maritime Delimitation and Territorial
Questions between Qatar and Bahrain, the International Court of Justice (ICJ) stated
that:
The Court observes that the concept of a single maritime boundary does not stem from multilateral treaty law but from State practice, and that it finds its explanation in the wish of States
22 The East China Sea is the area from latitude of 33 o 17’ North to the southern tip of Ryukyu Islands
or the northern tip of Taiwan. Its average depth of water is about 50 metres and the continental shelf,
which reaches a depth of less than 100 metres, extends eastward almost up to the Okinawa Trough.
23 In fact, the Japanese government expressed regret at the new Chinese gas field, Hakkaku-tei,
located in the distant area of the Chinese side of the median line. We can take this Japanese attitude
as expressing externally its intention to insist that the area extending up to 200 nautical miles is
under dispute. Yumi Nishimura (2006).
25
area stretches in the area west of the median line to the Okinawa Trough (boat-shaped
basin).
22
China has adopted the natural prolongation theory for the continental shelf and
has claimed that its sovereign right covers the shelf extending to the Okinawa Trough.
Noteworthy is the fact that China operates an offshore platform to fully exploit an oil
and gas field on the Chinese side, about 4.5 km from the median line (the so-called
Chunxiao gas field problem). In contrast, Japan has claimed that the Okinawa Trough
is just a dent, and does not represent any physical limit of the continental shelf, and
that the median line between the two States should be the basis for delimiting their
boundary in the East China Sea that is less than 400 nautical miles wide between
them. This means that Japan sees an overlap of the Japanese and Chinese 200 nautical
mile EEZs as being in dispute, and views the median line as a provisional boundary
for a transitional period until the two States delimit a final boundary by agreement.
Japan has adopted the position that it will maintain its title under international law
to its EEZ or continental shelf extending up to 200 nautical miles from its baseline
until a bilateral boundary is delimited by agreement.
23 This position could be taken
as affecting the significance of the median line as provided by the Japanese domestic
Law on the Exclusive Economic Zones and the Continental Shelf. As for this point,
Japan has explained that its law unilaterally sets Japan’s law enforcement limits and
does not affect its external position.
UNCLOS does not necessarily require any single boundary covering both the
EEZ and continental shelf. This is because the legal title to the EEZ is based on the
standard distance of 200 nautical miles, while the title to the continental shelf depends
on the continuity or natural prolongation of the onshore geological structure (Articles
57 and 76 of UNCLOS). In fact, the continental shelf is characteristically different
to the EEZ. The continental shelf belongs to coastal States ipso facto and ab initio,
and the legal title to the shelf does not depend on effective or nominal occupancy,
or explicit declarations. In contrast, explicit acts are required for establishing the
EEZ. In waters where the EEZ is established, the continental shelf extending up to
200 nautical miles from the coastline is covered by the EEZ. Only any continental
shelf portion beyond the EEZ boundary is related to the natural prolongation theory.
For these reasons, States have tended to delimit common boundaries for EEZs and
continental shelves. In the case concerning the Maritime Delimitation and Territorial
Questions between Qatar and Bahrain, the International Court of Justice (ICJ) stated
that:
The Court observes that the concept of a single maritime boundary does not stem from multilateral treaty law but from State practice, and that it finds its explanation in the wish of States
22 The East China Sea is the area from latitude of 33 o 17’ North to the southern tip of Ryukyu Islands
or the northern tip of Taiwan. Its average depth of water is about 50 metres and the continental shelf,
which reaches a depth of less than 100 metres, extends eastward almost up to the Okinawa Trough.
23 In fact, the Japanese government expressed regret at the new Chinese gas field, Hakkaku-tei,
located in the distant area of the Chinese side of the median line. We can take this Japanese attitude
as expressing externally its intention to insist that the area extending up to 200 nautical miles is
under dispute. Yumi Nishimura (2006).