An “ofuda” is an item that contains the spirit of the kami of a jinja, which devotees can receive from the jinja in order to venerate the kami in their own home. Physically, they are wooden boards, with the name of the kami or jinja written on, and the spirit of the kami is instilled in a special matsuri at the jinja. Ofuda are the only essential item on a kamidana, a shelf where kami are venerated in the home; if you have no ofuda, you have no kami on your kami shelf.
People in Japan get ofuda by visiting their local jinja, making an offering (typically around ¥1,000), and receiving an ofuda. This is how the Shinto establishment thinks that it should work, and they strongly discourage any form of mail order; people should go to the jinja in person to get the ofuda, and with the exception of Jingū at Isë, if you cannot visit a jinja, you should not have the ofuda.
In addition, you are supposed to replace the ofuda every year. It isn’t exactly that they expire and stop working, but cyclical renewal of the kami is an important feature of Shinto practice, and replacing ofuda (and omamori amulets) is part of this. Obviously, visiting one’s local jinja at least once a year is not a major burden for someone who wants to venerate the kami in their own home. It can be more of a problem if you have a strong personal link to a jinja that is a long way from you, but even a trip from Okinawa to Hokkaido is practical on an annual basis.
Things are much more difficult if you are not living in Japan.
Yesterday, I was at Jinja Honchō to talk about where various projects are up to, and I also raised this issue. Someone who visits Japan, receives an ofuda, and sets up a kamidana in their home faces a serious problem when the time comes to replace the ofuda. Someone who wants to practise Shinto but has never visited Japan has an even more serious problem. There is a jinja in the USA (Tsubaki Grand Shrine of America) that will send you an ofuda in return for a donation, but they, naturally, only offer their own ofuda (and Jingū Taima, the ofuda from Jingū). If you want an Inari ofuda or a Tenjin ofuda, you are out of luck.
This is a difficult problem. In practical terms, I think ofuda would have to be sent by post, and the places despatching them would need to take credit cards. Both of these are looked on with concern by Jinja Honchō, for religious reasons. First, ofuda are sacred, and should not really be simply dropped in the mail. (That said, several jinja have sent me ofuda in that way, albeit after I visited.) Second, taking credit cards makes the jinja look a lot like a business, and it is important that ofuda not be seen as products, in that sense. Third, if the service were available, people might want to use it in Japan, and they really want to discourage that. Actually visiting jinja is fundamental to Shinto practice.
At the moment, there are very few people outside Japan who want ofuda, but if Jinja Honchō’s plans to reach out to more tourists are successful, we can expect the numbers to increase. My concern is that, if Jinja Honchō does not work out a good solution to the problem, commercial companies will step into the gap, sending people to jinja to get ofuda and then posting them on (with a huge mark-up, most likely). Unfortunately, I cannot solve the problem; I can only make sure that Jinja Honchō is aware of it, and thinking about it. So that is what I have done.