Recruiting websites, agencies, etc.

[NomDeForum]

I live in Kansai.

This one phrase is guaranteed to kill any budding business conversation.

[beanhead]

Because the industry I've worked in exclusively for more than 25 years is declining and my main skill is therefore not as widely sought and valued as once it was, I am confronted suddenly by the prospect of doing something completely new.

So you are around 50, I guess?
It will be difficult to start in something completely new at that age. Not impossible, but tough.

A couple of suggestions:
i) study. There are a bunch of online courses available, some free, some not, which may help. If you were in Tokyo I would suggest Temple Continuing Education classes if there are any relevant ones. I don't know if the larger universities in Kansai offer similar evening classes. You said your Japanese is fluent so looking at local classes is a start.

ii) network. Do some searches for networking events in fields you are interested in. In my experience, this seems to be more common in international communities than Japanese-only. My Japanese colleagues have often networked mostly within the company, rather than more generally with others in the same industry (a broad generalization, I know).
Just getting out and meeting people to find out about different companies and jobs may be helpful.

Both of these suggestions are based on you knowing what area you would like to move into. So I think you need to try and narrow this down. Something adjacent to your current industry, or something where your skills will be transferable, will be easier than something unknown. I don't like your chances of breaking into finance at your stage in life, for example.

[NomDeForum]

these suggestions are based on you knowing what area you would like to move into. So I think you need to try and narrow this down.

And there it is: the step on which I must fall down or else o'erleap.

Thanks very much for your response. I like the idea of studying to learn some new skills. I get the feeling that the combination of studying and networking - even if they don't lead to a job directly - will at least lead to the answer to that simplest but hardest of all questions: "Well, what kind of work do you want to do?"

[William]

For what it's worth, I'm currently studying at Temple Continuing Education class, not because I'm in a similar situation, but because I always try to upgrade my skills. Going back to university is always nice, at least for me, since I love studying and would have spent my life in universities, should money not be a concern.

It seems, however, that you're not still in the "emergency" phase and still have your old job for the time being. Why not use this relative security to launch your own small business or try freelancing? UpWork and similar websites seem to have a lot of different talents. Maybe there's a way you could casually explore for the time being?

[NomDeForum]

For what it's worth, I'm currently studying at Temple Continuing Education class, not because I'm in a similar situation, but because I always try to upgrade my skills. Going back to university is always nice, at least for me, since I love studying and would have spent my life in universities, should money not be a concern.

Thanks for responding. Much appreciated.
For inspiration's sake - if you don't mind my asking - what are you studying at Temple?

[William]

Thanks for responding. Much appreciated.
For inspiration's sake - if you don't mind my asking - what are you studying at Temple?

I'm not sure it will be useful for you, unfortunately.
It's Japanese labour law. I do not think you could impact your career on that, except if you're already in a position where this is the knowledge you need.