Hokkaido

• JFE Bars & Shapes Corporation/Toyohira
• Shimizu Steel, Ltd.
• Nippon Steel Corporation/Muroran
• Japan Steel Works M&E, Inc.

Tohoku

• Itoh Iron & Steel Co., Ltd./Ishinomaki
• Kosaka Smelting & Refining Co., Ltd.
• JFE Steel Corporation/Sendai
• Tokyo Tekko Co., Ltd./Hachinohe

Kanto

• Asahi Industries Co., Ltd.
• Itoh Iron & Steel Co., Ltd./Tsukuba
• Oji Steel Co., Ltd.
• Kanto Steel Corporation
• Godo Steel, Ltd./Funabashi
• Sanko Seiko Co., Ltd.
• JFE Bars & Shapes Corporation/Kashima
• JFE Bars & Shapes Corporation/Tobu
• Jonan Steel Corporation
• Chiyoda Steel Co., Ltd.
• Tokyo Kotetsu Co., Ltd.
• Tokyo Steel Manufacturing Co., Ltd./Utsunomiya
• Tokyo Tekko Co., Ltd./Oyama
• Nippon Yakin Kogyo Co., Ltd.
• Mukoyama Steel Works Co., Ltd.

Chubu・Hokuriku

• Aichi Steel Works, Ltd.
• Otani Steel Corporation
• Kyoei Steel, Ltd./Nagoya
• Komatsu Ltd.
• Daido Steel Co., Ltd./Chita
• Daido Steel Co., Ltd./Shibukawa
• Topy Industries, Ltd.
• NGK Insulators, Ltd.
• Nippon Koshuha Steel Co., Ltd.
• Nachi-Fujikoshi Corporation
• Hokuetsu Metal Co., Ltd.
• Mitsuboshi Metal Industry Co., LTd.
• Yamaguchi Kogyo Co., Ltd.

Kinki

• AGC Ceramics Co., Ltd.
• Osaka Steel Co., LTd./Sakai
• Kishiwada Steel Co., Ltd.
• Kyoei Steel, Ltd./Hirakata
• Kubota Corporation
• Godo Steel, Ltd./Himeji
• Godo Steel, Ltd./Osaka
• Kobe Steel, Ltd.
• Sanyo Special Steel Co., Ltd.
• JFE Bars & Shapes Corporation/Himeji
• Shin Kansai Steel Corporation/Sakai
• Takuma Co., Ltd.
• Nakayama Steel Products Co., Ltd.
• Nakayama Steel Works, Ltd.
• Nippon Steel Corporation/Wakayama
• Yamato Steel Co., Ltd.

Chugoku

• Ube Steel Co., Ltd.
• Kyoei Steel, Ltd./Yamaguchi
• JFE Bars & Shapes Corporation/Mizushima
• Tokyo Steel Manufacturing Co., Ltd./Okayama
• Hitachi Metals, Ltd./Yasugi

Kyushu・Okinawa

• Osaka Steel Co., LTd./Nishi-Nippon Kumamoto
• Kyushu Steel Corporation
• Takunan Steel Co., Ltd.
• Tokai Steel Corporation