Kasho Ship Flag and the Noshima Murakami Family Documents
The Kasho Ship Flag (過所船旗, dated the 28th day of the 4th month of Tensho 9) and the Noshima Murakami Family Documents are a silk ship's flag of 1581 and a body of medieval letters handed down by the Noshima Murakami family, held by the Yamaguchi Prefectural Archives in Yamaguchi City, and were designated an Important Cultural Property in 2015.
The material descends through the Murakami family who served the Choshu domain as its naval corps. Their ancestors, the Noshima Murakami, were warriors, often called pirates, based on the islet of Noshima in the Geiyo Islands of the Seto Inland Sea, in present-day Miyakubo, Imabari.
Cultural Heritage Online lists one flag and 203 documents. The Kasho Ship Flag and the documents were designated on 4 September 2015.
Why They Are Protected
In the medieval Inland Sea, the Noshima Murakami kept their independence by switching allegiance among regional lords, and the central powers treated them as a force in their own right. Toward the end of the sixteenth century they drew closer to the Mori clan and in the Edo period became Mori retainers.
The documents include an order from the shogun Ashikaga Yoshiteru and letters from the Mori and Kobayakawa, from Oda Nobunaga, Toyotomi Hidenaga, Matsunaga Hisahide and Otomo Sorin, and from officials of the Toyotomi regime. The earliest is an undated letter of the 13th day of the 4th month from Hosokawa Takakuni, granting Murakami Takakatsu the stewardship of the Shiwaku Islands in Sanuki; the latest is a letter from Mori Terumoto dated 2 October 1599.
The Agency for Cultural Affairs says the collection shows vividly how the independent Noshima Murakami lost power under the Toyotomi ban on piracy and became Mori vassals. It ranks as the most complete body of evidence for how a warrior house that ran a fleet on the Inland Sea operated and changed during the Warring States period.
What to Look For
The Kasho Ship Flag is ink on plain silk, 53.4 centimetres high and 42.1 centimetres wide, mounted as a hanging scroll with its top batten and roller still in place. A large Murakami crest, the character 上 (kami) in stylised form, fills the centre. On the right is the addressee, the Hafuri family of priests at Itsukushima Shrine in Aki; on the left, the date and the signature and cipher of the clan head, Murakami Takeyoshi.
Kasho means a travel permit. Medieval Itsukushima Shrine sat on the Inland Sea shipping lanes and managed shipping and trade, and the agency believes the shrine asked the Noshima Murakami for a flag that would work as a pass. Flown from a ship, it allowed safe passage through Murakami waters: a permit for the sea.
If you get the chance to see the Kasho Ship Flag, notice how large the central crest is and how the addressee and sender are split to either side. The design puts the crest first so that it could be recognised from a distant ship.
Viewing Opportunities
The flag and documents belong to the Yamaguchi Prefectural Archives (150-1 Ushirogawara, Yamaguchi). They are not on permanent display, and whether and when they are shown varies by exhibition, so check the archives' programme if you hope to see them.
The archives' online catalogue lists the collection. For access to the originals or exhibition plans, contact the archives.
When the items are displayed, follow the venue's rules on photography.
- 📍 Plan Your Visit to Yamaguchi
- Find tours, activities & transport passes near Kasho Ship Flag (Tensho 9, 4th Month, 28th Day; Noshima Murakami Family Documents)
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Q&A
- What is the Kasho Ship Flag?
- A silk flag that Murakami Takeyoshi, head of the Noshima Murakami, issued in 1581 to the Hafuri priests of Itsukushima Shrine. It is thought to have served as a pass through Murakami waters.
- What do the Noshima Murakami Family Documents contain?
- Mainly letters from warlords and Toyotomi officials, including Ashikaga Yoshiteru, the Mori and Kobayakawa, Oda Nobunaga and Toyotomi Hidenaga. Cultural Heritage Online counts 203 documents.
- When were the Kasho Ship Flag and documents designated an Important Cultural Property?
- On 4 September 2015.
- Where can I see the Kasho Ship Flag?
- It is held by the Yamaguchi Prefectural Archives and is not on permanent display. Check the archives' exhibition schedule.
- How big is the Kasho Ship Flag?
- 53.4 centimetres high and 42.1 centimetres wide.
Basic Information
| Name | Kasho Ship Flag (Tensho 9, 4th Month, 28th Day; Noshima Murakami Family Documents) |
|---|---|
| Location | Yamaguchi Prefectural Archives, 150-1 Ushirogawara, Yamaguchi City, Yamaguchi Prefecture |
| Designation | Important Cultural Property (Historical Materials, Documents) |
| Year Designated | Designated 2015/09/04 (Heisei 27) |
| Quantity | 1 flag and 203 documents |
| Dimensions | Flag 53.4 cm high, 42.1 cm wide |
| Owner | Not listed in the Agency for Cultural Affairs database (held by the Yamaguchi Prefectural Archives) |
| Public Access | Not on permanent display. Check the archives' exhibition schedule |
References
- Agency for Cultural Affairs, Database of National Cultural Properties: Kasho Ship Flag and Noshima Murakami Family Documents
- https://kunishitei.bunka.go.jp/bsys/maindetails/201/00011690
- Cultural Heritage Online: Kasho Ship Flag and Noshima Murakami Family Documents
- https://online.bunka.go.jp/heritages/detail/417392
- Yamaguchi Prefectural Archives: Collection Search (Japanese)
- https://archives.pref.yamaguchi.lg.jp/msearch/cls_search/2704
Last verified: 2026.09.27