Ryujiro Kiyama

President at KOKEN BORING MACHINE CO.,LTD.

Net worth: 111 536 $ as of 29/11/2025

66 year

Producer Manufacturing

Consumer Services

Profile

Ryujiro Kiyama currently works at Kozo Construction Co., Ltd., as Chairman from 2019 and Koken Boring Machine Co., Ltd., as President & Representative Director from 2019.
Mr. Kiyama received his undergraduate degree from Kumamoto University.

Known holdings in public companies

Company	Date	Number of shares	Valuation	Valuation date
KOKEN BORING MACHINE CO., LTD. 0.26%	29/09/2025	23,000 ( 0.26% )	111 536 $	29/11/2025

Ryujiro Kiyama active positions

Companies	Position	Start
KOKEN BORING MACHINE CO.,LTD.	President	31/05/2019
Kozo Construction Co., Ltd.	Chairman	31/05/2019

All active positions of Ryujiro Kiyama

Training of Ryujiro Kiyama

Experiences
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Linked companies

Private companies	3
Koken Boring Machine Co., Ltd. Koken Boring Machine Co., Ltd. Trucks/Construction/Farm MachineryProducer Manufacturing Engages in the manufacture and sale of drilling grouting machines	Producer Manufacturing
Kumamoto University Kumamoto University Other Consumer ServicesConsumer Services Functions as a College/University	Consumer Services
Kozo Construction Co., Ltd.