Self-governing peoples · Korea and Japan · as at first light, 1 January 1200

Self-governing peoples of Korea and Japan

The coast of north-west Hizen and its islands (Hirado, the Gotō chain, the Kashima shore, the Karatsu bay) is held by a crowd of small warrior families who fight, trade and carry freight by sea and who go by the name of the district, Matsura.

They have no castle worth the name, no common head, and no written league yet; they meet to settle quarrels and to answer the Dazaifu or Kamakura together when it suits them. They are the first sea-people of Japan whom Goryeo will name as raiders, but the Korean record is of 1223; before that nothing is attested.

Who rules

Name
not known as a single head
Title
Council of equals (tō, a league of small warrior families)
Family
Matsura families with a Saga Genji claim, and boat-warrior followers
Confidence
low

English Wikipedia (Matsura clan) describes the Matsura-tō as petty military families of Hizen with roots in the 11th century; the league as a written document is of the 13th century (brief).

Overlord

nominally the Dazaifu and Kamakura's constable; neither exercises day-to-day rule on the coast

What the realm holds

  • The Matsura coast of Hizen: Hirado, Ikitsuki, the Karatsu bay and the Kashima shore
  • The Gotō islands (Fukue, Naru, Wakamatsu and the northern isles)

How it was acquired

Local descent: families of the 11th century onward holding as stewards (jitō and gesu) of the estates of the coast.

Allies and rivals

Allied by marriage and shipping with the Munakata priests and the Hakata merchants; rivals of the Kanzaki and Saga estates inland.

The realm that morning

No war in force. The coast is quiet; the Song ships go to Hakata, not to the Matsura harbours. No raiding of Korea is recorded before 1223.

Wealth

Freight, fish, salt, the escort of merchant ships; their reputation for taking cargo is later.

Military

Boat-warriors in small ships; no numbers in any source we could read.

Threats

  • A Kamakura constable or a Dazaifu steward who tries to hold the coast (the Shōni, later)

What the year holds

What happened next, if nothing in play changes it. Each event carries what it depends on and what would stop it.

  1. 1223Goryeo's record names Japanese raiders on its coast (the earliest wakō notice)Depends on: The Matsura shipmen are among the raiders, per later tradition Stopped by: n/a

Where the sources disagree

Evidence: One English Wikipedia page and the brief; the Matsura-tō's own documents are of the 13th century and later.

On the map: The extent of the league's reach in 1200 is not pinned; the block is the later Matsura country.

Sources and studies

  1. OMNIA kja regional brief (KJA_BRIEF.md), the campaign's dated traps and realm table
  2. OMNIA board notes and places for area kjw (starting lead only, checked against the sources)
  3. Matsura clan, English Wikipedia

Last revised 4 November 2026. Published 4 November 2026. Suggest a correction on the OMNIA Discord.