Kiyoshi Hashimoto's machinery factory outside Tokyo should be buzzing with industry. Instead, it's so quiet you can hear him practising the recorder.

The 82-year-old entrepreneur founded his company nearly 40 years ago, but well past retirement age he has neither a successor nor a buyer for a business that retains loyal clients.

It is a problem that Japan's government warns could affect up to a third of all small businesses in the country by 2025, as the country's population shrinks and ages.