Kawamura Zuiken was influential in the development of Japanese ocean trading routes.

[citation needed] He established a new route for the shipment of rice from the Tohoku region of northern Japan to Edo, significantly reducing the time required for transportation.

This new route, known as the Higashimawari (Eastern Circuit), involved transporting rice down the Abukuma River to Arahama on the Pacific coast, and then shipping it around the Boso Peninsula to Edo.

In 1672, he devised a second route, the Nishimawari (Western Circuit),[1] which transported rice from northern Japan through the Shimonoseki Straits and the Inland Sea to Edo, reducing the transport time to three months.

[2] In 1683, he undertook a project to clear the outlets of the Yodo River in the Osaka region.