Hideo Hoshino

Yamanaka Ohya Koi Farm

Yamanaka Oya Koi Farm is a well-established koi breeding operation located in the Yamakoshi area of Nagaoka City, Niigata Prefecture, Japan. The farm is headed by Hideo Hoshino, who operates under the breeder name “Yamanaka Oya.”

Specialization

Yamanaka Oya Koi Farm offers a broad range of koi varieties, with a strong focus on:

Shiro Utsuri
Go-Sanke (Kohaku, Sanke, Showa)
Hariwake
Midori Koi and Ai Goromo
Various Hikarimono and the unique Aya Wakaba

The Aya Wakaba is a patterned Midori-type koi, known for its soft, leafy tones and unusual color combinations, making it a standout among modern koi varieties.

Farm Overview

Location: Yamakoshi, Nagaoka City, Niigata Prefecture, Japan
Current Owner: Hideo Hoshino
Facilities: Approximately 30,000 m² of space, including mud ponds and indoor growing systems
Production: Roughly 10,000 tosai and 1,500 nisai produced annually

Reputation

Yamanaka Oya is respected for its versatility and for producing koi with refined patterning and excellent skin quality, especially in the Shiro Utsuri category. The farm’s koi are appreciated for their sharp sumi contrast, clean white base, and consistent quality. While not one of the highest-volume breeders, Yamanaka Oya is known for careful selection and producing koi with unique and distinctive traits.

In Summary

Yamanaka Oya Koi Farm specializes in Shiro Utsuri, Go-Sanke, Midori-type koi, Aya Wakaba, and various Hikarimono. Under the leadership of Hideo Hoshino, the farm emphasizes quality and variety over volume, maintaining a reputation for producing koi with excellent finish, structure, and unique appeal among Japanese and international enthusiasts.