Editing Geography of Japan (section)

===History===
During the [[Pleistocene]] (spanning 2.58 million-11,700 years ago) glacial cycles, the Japanese islands may have occasionally been connected to the [[Eurasia|Eurasian Continent]] via the [[Korea Strait]] and the [[Korean Peninsula]] or Sakhalin. The Sea of Japan was considered to be a frozen inner lake because of the lack of the warm [[Tsushima Current]]. Various plants and large animals, such as the elephant ''[[Palaeoloxodon naumanni]],'' migrated into the Japanese archipelago.<ref name = sealevel>{{cite journal |last1=Park |first1=S.-C. |last2=Yoo |first2=D.-G. |last3=Lee |first3=C.-W. |last4=Lee |first4=E.-I. |title=Last glacial sea-level changes and paleogeography of the Korea (Tsushima) Strait |journal=Geo-Marine Letters |date=26 September 2000 |volume=20 |issue=2 |pages=64–71 |doi=10.1007/s003670000039 |bibcode=2000GML....20...64P |s2cid=128476723}}<!--|access-date=2 April 2011--></ref>

The Sea of Japan was a landlocked sea when the [[land bridge]] of [[East Asia]] existed circa 18,000 BCE. During the glacial maximum, the marine elevation was 200 meters lower than present. Thus, [[Tsushima island]] in the Korea Strait was a land bridge that connected Kyushu and the southern tip of Honshu with the Korean peninsula. There were still several kilometers of sea to the west of the Ryukyu islands, and most of the Sea of Japan was open sea with a mean depth of {{cvt|1,752|m|ft}}. Comparatively, most of the [[Yellow Sea]] (Yellow Plane) had a [[semi-arid climate]] (dry steppe) because it was relatively shallow, with a mean depth of {{convert|44|m|abbr=on}}. The Korean Peninsula was landlocked on the entire west and south sides of the Yellow Plane.<ref>{{cite book |url=https://books.google.com/books?id=W_Hdu9QrD9YC&pg=PA16 |title=Pre-Industrial Korea and Japan in Environmental Perspective |first=Conrad D. |last=Totman |year=2004|publisher=BRILL |access-date=2007-02-02 |isbn=978-9004136267}}</ref> The onset of the formation of the Japan Arc was in the [[Early Miocene]] (23 million years ago).<ref name="Kameda 2011">Kameda Y. & Kato M. (2011). "Terrestrial invasion of pomatiopsid gastropods in the heavy-snow region of the Japanese Archipelago". ''[[BMC Evolutionary Biology]]'' '''11''': 118. {{doi|10.1186/1471-2148-11-118}}.</ref> The Early Miocene period was when the Sea of Japan started to open and the northern and southern parts of the Japanese archipelago separated from each other.<ref name="Kameda 2011"/> The Sea of Japan expanded during the [[Miocene]].<ref name="Kameda 2011"/>

The northern part of the Japanese archipelago was further fragmented until the [[orogenesis]] of the northeastern Japanese archipelago began in the [[Late Miocene]]. The orogenesis of the high mountain ranges in northeastern Japan started in the Late Miocene and lasted into the [[Pliocene]].<ref name="Kameda 2011"/> The southern part of the Japanese archipelago remained a relatively large landmass. The land area expanded northward during the Miocene.<ref name="Kameda 2011"/>

[[File:Last_Glacial_Maximum_Vegetation_Map.svg|thumb|upright=1.5|Vegetation during the [[Last Glacial Maximum]] (16,000 BCE)]]

During the advance of the [[Last glacial period|last Ice Age]], the world sea level dropped. This dried up and closed the exit straits of the Sea of Japan one by one. The deepest, and thus the last to close, was the western channel of the Korea Strait. There is controversy as to whether the Sea of Japan became a huge, cold inland lake.<ref name = sealevel/> The Japanese archipelago had a [[taiga]] biome (open boreal woodlands). It was characterized by [[coniferous]] forests consisting mostly of pines, spruces, and larches. Hokkaido, Sakhalin, and the Kuril islands had [[mammoth steppe]] biome (steppe-tundra). The vegetation was dominated by palatable high-productivity grasses, herbs, and willow shrubs.