Kaisen

A model of a Ryukyuan tribute ship, on display at the Okinawa Prefectural Museum

• Other Names: 進貢船 (shinkou sen), 接貢船 (sekkou sen)
• Japanese: 楷船 (kaisen)

Kaisen were a type of Ryukyuan ship used to carry official missions to Kagoshima. They were typically ships that had previously been used to sail to China, as either shinkôsen ("tribute ships" carrying official Ryukyuan tribute missions to China) or sekkôsen (ships which went to bring Ryukyuan officials back from China, often transporting trade goods as well); after three or so such journeys to China, a ship would often be stripped of its weaponry, and thus transformed into a kaisen, to be used for journeys to Kagoshima.

While shinkôsen carried official missions to China roughly once every other year, sekkôsen traveled to Fuzhou in the alternating years, ostensibly to bring the previous year's mission back home; however, both shinkôsen and sekkôsen also carried considerable amounts of tribute/trade goods, playing a vital role in the flow of silver, herbal medicines, a variety of luxury goods, and other products, between China, Ryûkyû, and Japan.

Design and Decoration

Kaisen were typically around thirty meters long and eight meters wide, with a main mast roughly thirty meters in height. They were of a nearly identical design to Chinese junks plying the same waters.

The sails, like those of sabani (Okinawan fishing canoes), were made in a manner closely related to that used in China. Thin slats of bamboo were interwoven to form a six-sided lattice, a pattern or method known in Japanese as mutsume ami (六つ目編み). Branches, leaves, or grasses were then interwoven into the lattice to form a relatively solid sheet which could catch the wind. As in traditional Chinese "junks," the sails were held up not just by one or two static standing crossbars (as in European sailing ships), but rather by a series of numerous bamboo cross-bars which were raised and lowered as part of the sail.

Fringed banners in red and yellow, with a red sun at the center, served as an emblem of the Ryûkyû Kingdom (the king of Ryûkyû was often referred to as tedako, or "son of the Sun"). Though the use of yellow was officially restricted in Qing Dynasty China, it being a color symbolic of the Imperial establishment, these banners were one way in which Ryûkyû expressed its own identity as an independent kingdom, and the Qing are said to have raised no objections to Ryûkyû employing Imperial shades of yellow on their ships' banners in this way.

A number of streamers were flown from the top of the mast and from the rear of the ship. They are said to have been intended to resemble or invoke the shape of koi, dojô, or other fish.

References

• "Sekkôsen," Okinawa Compact Encyclopedia, Ryukyu Shimpo, 1 March 2003.
• "Tribute Ship to China Model," gallery label, Okinawa Prefectural Museum.