Watarishima is the court's old name for the peninsula and coast of Hokkaido across the Tsugaru strait.
In 1200 its people are Satsumon-Ainu villagers, fishing salmon, hunting and trading with Tsugaru and Dewa across the strait, using iron and cloth that come from the south; no chief and no castle is known (the Japanese lords of Matsumae are of the fifteenth century and later). It is the nearest Ezo ground to Kamakura's northern claim and the place where the Japanese meet the Ezo most often.
Who holds it
- Title
- No ruler: the villages (kotan) of the south-west Hokkaido coast
- Confidence
- low
Archaeology (English Wikipedia: Satsumon culture, Ainu people); the Japanese court called the peoples of the southern coast 'Watarishima Emishi'.
What it holds
- Salmon rivers and coast villages
- Trade with Tsugaru
Allies and rivals
Trade partners in Tsugaru and Dewa.
How things stand that morning
What Kamakura names or controls: nothing known. What stops it: the strait, the cold and the lack of any administrative interest.
Wealth
Fish, furs, feathers (recalled); no figure.
Threats
- Hard winters
Where the sources disagree
- Matsumae and the Andō are later.
Evidence: Archaeology and general knowledge.
On the map: Soft outline.
Primary sources for Ezo (Hokkaido, Sakhalin tip, south Kurils)
Chronicles, registers, sagas and inscriptions written in or near 1200 that cover this entry. Each has its own page with editions, translations and where to read it.
- Mirror of the East, Anonymous; compiled by officials of the Kamakura shogunate (compiled about 1300 from the shogunate's records, diaries and family documents). The Kamakura house's own chronicle, in daily entries. Read online
Sources and studies
- KJA_BRIEF.md and the OMNIA board for sheet kja (the lead's notes: [own] computation, [not yet checked against the source] recollection, [en] English Wikipedia)
- Azuma Kagami (the Kamakura chronicle), Kenkyu 10 to Shoji 2 entries, recalled and through the brief; ja.wikipedia and ja.wikisource were refused in this session, so no entry was re-read
- Jeffrey P. Mass, Warrior Government in Early Medieval Japan (1974), from memory; the archive.org full text could not be opened
- English Wikipedia: Satsumon culture (read this session; thin)
Last revised 4 November 2026. Published 4 November 2026. Suggest a correction on the OMNIA Discord.