Age restriction for car rental in Japan

I've visited Japan on several occasions but had always used public transport to get around. For my next visit I intend to visit more rural areas and therefore thinks that renting a car would be a better option to get around.
However I just turned 70 last month and there seems to be some new restrictions for travelers who reached this milestone in their lives, an example being travel insurance becoming more expensive with less coverage.
My question is whether there are added restrictions for car rental in Japan for customers 70 years and older? If there are what would these restrictions be?

I've only read about being over 21 for age restrictions on the rental car websites.

Quickly looking at Orix, they have 18 minimum (an international convention), but don't show a maximum. Other references I saw talked about 70 or 75 because of insurance. However, if your drivers license and IDP are valid, looks like the "eligible to rent" flow chart on (say) the Toyota-rent-a-car site gets passed.

You could try a dummy booking and when it gets to the date of birth and try different birth years. Have you called a local company and asked what it's like where you are - that might give some clues.

I was in japan a few months ago, renting a car from Orix Sapporo, no question asked, I am seventy.

I rented a car from Toyota-Rent-a-car Zushi, about a year ago when I was 70 yrs old. I had an International Drivers Licence, obtained in my own country, which included all personal details from my drivers licence, including photo and birthdate, and I had no problem at all. The agent took a photocopy, plus a copy of my passport I think, and I filled out a rental agreement, signed, and they gave me a station wagon. I had booked it online.

There is no thing that can not contract a rent-a-car just because "elderly".

However, in Japan's driver license system,
drivers over the age of 70 are obliged to take special lectures at the time of renewal.
https://youtu.be/uIlqciiB2WE
This is because accidents due to elderly drivers are on an increasing trend,
http://www.keishicho.metro.tokyo.jp/smph/kotsu/jikoboshi/koreisha/kore...
but it is not related to foreign travelers with IDP.

I think that this question is also beneficial.
https://www.japan-guide.com/forum/quereadisplay.html?0+166824

Thanks everyone who replied with useful info and suggestions.