This one bounces around a bit, making the narrative (such as it is) hard to follow.

The Canto‘s opening setting is Japan under the Shogunate. But it gets confusing from there. Firstly, it appears to be, at least in part, about the early trading contacts with Europe. Certainly, there is some conversation about the introduction of Christianity to the island:

And because of the hauteur of
         Portagoose prelates, they drove the Xtians out of the Japan
till were none of that sect in the  Island

But it quickly moves back the mainland, with switches between Korea (‘Corea’) and China (and the ‘Tartars’ get mentioned again – though I have been assuming that this word is used simply to refer to those viewed as barbarians by the Chinese).

The intermittent story of a Père Ricci and his work in the East (the historical Ricci was a Jesuit Father) also features, though in a very fragmentary fashion.