Jinshin Yakujo (壬申約条)

Jinshin Yakujo were rules for immigration that were issued by Yi Dynasty Korea against So clan in Tsushima Province in 1512. The friendly relationship between Japan and Korean Dynasties had been severed due to the Sanpo disturbance in 1510. The Jinshin Yakujo was imposed one-sidedly by the Korean Dynasties as a condition for the resumption of the relationship. Even though the name was changed to the Eisho treaty after the Japanese invasion to Korea during the Meiji period, it was still not in an appropriate form of a treaty.

The So clan, suffering from dire poverty caused by the severance of friendly relations with Korean Dynasties as a result of the Sanpo disturbance, placed its reliance on Yoshioki OUCHI. With the help of Hochu, who was dispatched as an envoy of Yoshitane ASHIKAGA, the seii taishogun (literally, "great general who subdues the barbarians") of the Muromachi bakufu (Japanese feudal government headed by a shogun) under the guardianship of Yoshioki, the So clan negotiated the resumption of the relationship with the Korean Dynasties. The Jinshin Yakujo was issued as a consequence of the negotiation.

Eliminating kokyowa (Japanese people who lived in Sanpo, namely, Enbo, Pusanpo, and Naijiho or Seiho).

Limiting the open port to Seiho (port of Sei) only.

Reducing the number of toshu saikensen (ships of head family of the So clan to dispatch an annual envoy to Korea) from fifty, which number was determined in the Kakitsu Treaty, to twenty-five.

Banning saikensen (ship to dispatch an envoy to Korea) owned by powerful branch families of the So clan, tokusosen (ship to dispatch an envoy to Korea to deliver immediate report), and koriwasen (ship for trading with Korea).

Reducing the amount of sanshimai (rice given by Korea) and sanshito (beans given by Korea) given by the Yi Dynasty Korea to the So clan in Tsushima from 200-koku (a unit of volume of rice: 1-koku is 180.39 liters), which the amount was determined in the Kakitsu Treaty, to be 100-koku.

Reducing the number of Jushokunin (Japanese given Korean government post by the Yi Dynasty Korea) and Jutoshonin (Japanese given Korean government evidence called 'Tosho' to be granted special privileges in trading) by re-examining them and disqualifying those who were in name, but not in deed.

This is the main contents of the Jinshin Yakujo. The So clan succumbed to these demands and the relationship with Korean Dynasties based on these rules lasted until Toyotomi Hideyoshi's Korean Invasions.