Ōyama Seichaen is a family farm and factory in Higashi-Sonogi, run by Yoshitaka Ōyama, the fourth generation. Nine hectares, and every step happens on the farm: planting, tending the gardens through the year, harvesting, processing and packing. The organic fertiliser is made there too.

The farm sits on the mountains facing Omura Bay. The difference in temperature leaves fog across the slopes in the morning, and between that, the soil and the sea breeze the tea takes on a flavor you do not find elsewhere.

Their tamaryokucha has won the Prime Minister's Award, and the Minister of Agriculture, Forestry and Fisheries Award five years in a row.