Ryujiro Kiyama

President at KOKEN BORING MACHINE CO.,LTD.

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

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%	2025-09-29	23,000 ( 0.26% )	111 536 $	2025-11-29

Ryujiro Kiyama active positions

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

All active positions of Ryujiro Kiyama

Training of Ryujiro Kiyama

Experiences
Positions held

Active

Inactive

Listed companies

Private companies

See the detail of Ryujiro Kiyama's experience

Connections

1st degree connections

1st degree companies

Male

Female

Members of the board

Executives

See the personal network

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.