Globally Important Agricultural Heritage Systems (GIAHS)

Osaki Kôdo's Traditional Water Management System for Sustainable Paddy Agriculture, Japan

GIAHS since 2017


Detailed Information



Global importance

Osaki Kôdo water management system is an example of farmers’ adaption and ingenuity to face natural disadvantages from the environment. Indeed, this region has to face violent wind, cold temperature and droughts. Whereas agriculture could seem difficult to be developed in such an environment, Osaki Kôdo is a good example of resilience.

Food and livelihood security

In Osaki Kōdo, farmers have grown a diversity of crops including soy bean, wheat and vegetables to avoid hunger in times of poor harvest and support their livelihoods through diversified sustenance, not limited to growing rice. This integrated agricultural system supports the continuation of paddy agriculture and enables the sustained production and supply of various agricultural produce centred on rice, which is the staple food of the Japanese and serves as the basis of the Japanese economy and culture.

Other activities are also taking place such as forestry and charcoal-making, silkworm breeding, horse breeding and making wooden crafts for daily use. Approximately 20% of the labour force population, or 20,451 people, still engage in integrated agricultural practices centred on rice production today. 7,185 commercial farm households rely on profits from agricultural produce sales.


In addition to soy bean and wheat, vegetables such as scallions, tomatoes and Chinese cabbages as well as flowers such as chrysanthemums, pears and other fruit and traditional vegetables such as the Kozena-daikon, Onikoube-na, Matuyama-seri, and Kamiibano-satoimo, are grown in fields close to the igune (residence). An igune is composed of a variety of species, including subcanopy trees such as Japanese alders, which can grow in wetlands, cedar, bamboo and hinoki cypress, as well as understory trees.

The complex mixture of trees has supported people’s lives. This unique landscape embracing rice paddies, igune, channels and reservoirs passed down from the Edo period contributes greatly to the biodiversity of the local paddy field ecosystem where animals including many bird species, frogs, snakes, and dragonflies travel between rice paddies and igune.

Local and traditional knowledge systems

The people of Osaki Kōdo have exerted much effort into achieving both water use and flood prevention. They have built intake weirs, tunnels and drainage tunnels, reservoirs and networks of irrigation and drainage channels, thus securing the means for irrigating and draining water, without which agriculture in the Osaki region would not be possible.

They have also implemented various preventive measures against yamase winds, including ingeniously taking advantage of water temperatures to raise seedlings, applying “deep-water management” (raising paddy water levels), and stopping the irrigation water flow during the daytime. In anticipation of floods, flood control basins have been created to reduce inundation damage.

The lives of local farmers are supported by the igune, woodlands planted around houses in protection against floods and winter northwesterly winds. As “forests floating in rice paddies,” they interconnect with surrounding rice paddies and water channel networks.

Comprehensive crop-livestock farming is also popular in this region. The breeding of beef cattle, dairy cows, pigs and egg-laying hens contribute to stable farm operations. Animal manure are made into compost and returned to the farmland as an important organic resources that support the fertile soil of Osaki Kōdo.

Furthermore, in Osaki Kōdo, which is exposed to a strong northwesterly wind, rice is dried under the sun using a traditional method called “bōgake” that involves hanging the straw radially around a pole.

Culture, values system and social organisations

Such water coordination efforts were performed mainly by keiyakukō, local land-based mutual assistance organization among farmers. In times of drought, the bottom-up water users’ organization established schemes based on exchange and agreement between upstream and downstream farmers to enable the sharing of water. Playing an indispensable role in the farmer-led coordination of such sophisticated joint water management, the keiyakukō has been continued across the area river basin.

Farming practices generated nature-worshiping folk beliefs, including worshiping the mountains where water is sourced, agricultural rituals and folk performing arts that are performed in prayer or in appreciation of a bountiful harvest, and the tōji culture of going to the hot springs to recover from the fatigue of hard agricultural labor. Furthermore, a rich and diversified local food culture was born, including mochi (rice cakes) cuisine, which was enjoyed in between stages of rice production; fermented food such as sake, miso (soybean paste) and soy sauce; and loaches and crucian carps, which are byproducts of fishing in the rice paddies.

Landscapes and seascapes features

The igune of Osaki Kōdo continues to be a part of the local landscape. When the rice paddies are filled with water during rice-planting season when the seedlings have yet to grow, they create a distinctive landscape with forest islands floating within the wet fields.

As a result of a traditional water management system that enabled paddy agriculture and the maintenance of livelihoods in a climate, Osaki Kōdo has developed a unique landscape that support farmers livelihoods and lives as well as a rich ecosystem through mosaic land use embracing channels carrying the blessings of water, rice paddies and igune scattered in the landscape like forests floating in the rice paddies. The mosaic land use based on an ingenious water management system contributes to the conservation of rich biodiversity and provides a habitat for frogs, spiders, dragonflies and other indigenous natural enemies of pests. Osaki Kōdo has harnessed this symbiotic relationship between agriculture and the ecosystem, promoting the spread of environment-conserving agriculture.