Here are three example sentences I have read with this construction, with possible translations:
사실인즉 : to tell the truth
말인즉 옳소 : what he says is true.
기회인즉 좋은 기회다 : about the opportunity – it’s a good opportunity.
In the first and second example, if the translations are correct, 즉 seems to mean 'speech'. In the third example, 인즉 seems to be mean something like (ㄴ)은.
Is there a single translation that makes sense in all these usages?
Also (as I'm not sure what to tag this question!) is this a noun, or a particle?