Kenminsen means ships dispatched seventeen times to Ming China in the Muromachi period (the total number of ships was eighty-four) during the period of one and a half centuries from 1404 to 1547 for the purpose of Nichi-Ming trade (trade between Japan and the Ming Dynasty, China) (Kango trade). These ships were also called Kangosen since both governments issued a certificate called Kangofu in order to prove the visiting ships were lawfully registered ships for Nichi-Ming trade.
Kango trade started in 1401 when Yoshimitsu ASHIKAGA proposed to start the trade with Ming by dispatching a Buddhist monk Soa and a merchant in Hakata Koitomi and received 'Eiraku kangofu' from the envoy of Ming. Originally, the bakufu was the shipowner of Kenminsen and directly operated them. With the power of bakufu gradually declining, influential temples/shrines (Shokoku-ji Temple, Sanjusangendo Temple etc) or influential shugo-daimyo (territorial lords as provincial constables) (the Hosokawa clan, the Ouchi clan etc.) became the shipowners and traded in corporation with merchants in Hakata and Sakai as well as sailors in the towns located in the coastal region of Seto Inland Sea. The Hosokawa clan and Ouchi clan competed to seize the initiative of trade, clashed at Neiha in 1523 and finally the Ouchi clan monopolized the trade. As a result, Yamaguchi, the base of the Ouchi clan, prospered far more than Kyoto that was devastated by the Onin War.
As the record exists that the number of ships of the second Kenminsen fleet returned to Japan in 1406 was six to seven, it is presumed that the scale of six Kenminsen fleets which visited Ming until Yoshimochi ASHIKAGA ceased dispatching them in 1410 was within the same range. After twenty-one years of interruption, Yoshinori ASHIKAGA resumed the operation in 1432 and eleven fleets or fifty-one ships (seven ships were owned by the bakufu, one was owned by the Imperial Court and the rest were owned by the shugo-daimyo or temples/shrines) visited Ming until 1550.
According to "Boshi Nyuminki" written by Zen monk Tenyo Seikei, who visited Ming in 1468 at the behest of Yoshimasa ASHIKAGA, large ships, whose size were 700 to 1700 goku (a unit of ship size), were used for Kenminsen and 150 persons (including fifty sailors) were on board. According to "Nyumin shoyorei," ships of 500 to 2500 goku were on standby at Moji, Tomita, Kamiseki, Yanai, Onomichi, Tomo, Tajima, Innoshima and Ushimado respectively for the same fleet of Kenminsen. At any rate, it is considered that relatively large ships were used for Kenminsen. After the Onin War, the scale of Kenminsen was limited to three ships and 300 persons.
Kenminsen sailed using seasonal winds. Ships left for the Asian continent in Spring or Autumn using a northeast seasonal winds and returned to Japan after May using a west-southwest seasonal winds.
Judging from the fact that the production of permanent magnets made of magnetite began in the age of the Sung Dynasty, the compass was already invented by that time and the term 'magnetic pointer' is seen in the navigation book written in the Eisho era, it is considered that Kenminsen sailed using a primitive compass.
Starting from Sakai or Hyogo, Kenminsen passed the Seto Inland Sea, stopped at Shimonoseki or Hakata and sailed for Neiha by traversing the East China Sea in a linear fashion.
When the confrontation between the Hosokawa clan and Ouchi clan became serious, the Hosokawa clan avoided taking the Seto Inland Sea route that passed near Yamaguchi, the base of the Ouchi clan, and instead took the route to sail for Neiha via Urado and Shimoda in Tosa Province and Aburatsu and Bonotsu in southern Kyushu.
The structure of the hull
Unlike the case of Kentoshisen (envoy ships dispatched to Tang, China), ships of Kenminsen were not the ones that were newly built for exclusive use but the rented private ships (merchant ships). These rented ships were used for Kenminsen after conducting major renovation such as the installation of hull fittings suitable for ocean navigation and the expansion of cabins for diplomatic envoys or influential merchants.
The structure of the hull was Tanaita (shelf boards) structure using sawn timber as the component of Kawara (the components for the bottom of a ship), instead of the ones hollowed from a tree trunk, L-shaped strong components called Omoki for both sides and several layered Tanaita reinforced by many Funabari (beams fitted horizontally between the planks on the hull of a ship to withstand water pressure). Basic structure of Tanaita was either three layered structure consists of Nedana (the components to structure the lowest part of a ship), Chudana (the components to structure the middle part of a ship) and Uedana (the components to structure the upper part of a ship) or two layered structure without Chudana and in the case of large ships, four layered structure with two layered Chudana was also seen. The shape of bows varied widely depending on ships and Todate style of Ise ships, Miyoshi style of Bensai ships and the blending style of Futanari ships, whose upper side was box style and lower side was Miyoshi style, were seen. Iron anchors were used along with a winch. Such structure of the hull was the original model of Japanese large sailing ships and was succeeded by kitamae-bune (cargo ships that sailed the Japan Sea during the Edo period), Higaki-kaisen (a kind of cargo vessel) and Taru-kaisen (a kind of cargo vessels) in pre-modern times.
Handicrafts such as swords, spears, armor, fans and folding screens as well as mineral products such as sulfur and copper. Swords accounted for the large portion of export and their annual export sometimes reached to 30,000 to 40,000.
Copper coins (such as Eiraku-sen) of Sung, Yuan and Ming which were the basis of money economy in Japan, textile such as silk, lightweight fabric and gauze, raw silk thread, medicine, calligraphic works/ paintings and handicrafts. Continent culture introduced by Zen monks such as the Sung Study (Neo-Confucian), medicine, printing art, ceramic art and ink-wash painting.