My local jinja, Shirahata Hachiman Daijin, has just hung a new shimënawa at the entrance to the prayer hall. I chatted with the priests about it, and learned that this is only the fourth one in the fifty years since the sanctuaries were rebuilt.
This shimënawa is made of rice straw, so it is the “real thing”, but it seems that those are not easy to get. The company that made the last one is no longer in business, and it seems it was not straightforward to find another one. Either this one or the last one was from a company in Kyūshū, in southwestern Japan. (We were chatting. I didn’t take notes.)
Some of the other shimënawa in the precincts are made of plastic. They are fairly convincing — you might not notice if you only visited once. However, after multiple visits, it does become obvious. I got the distinct impression from the conversation that this was a matter of availability rather than cost or convenience. Larger jinja can get straw ropes because they can put large orders in months in advance, but it seems that there are simply not enough suppliers for all the jinja.
Historically, of course, the ujiko made their own shimënawa from their own rice straw, and that still happens in some rural jinja. There, it is sometimes a major event, where the techniques are passed down. However, most urban jinja do not have access to the straw, or people with the skills, and rural jinja that have the straw probably lack the craft skills in most cases.
This sort of problem is common. Things that were a standard part of historical life were incorporated into Shinto practice, and now there are very few people who can still create them. This is part of the changes that are inevitable over time, of course, but I would still like to see many of these practices preserved for as long as possible.