I am visiting Japan again in November. On my last visit this site helped me locate a lot of bonsai nurseries which was fantastic! I also visited the bonsai pine farming region. 

This trip I am keen to visit some nursarys and farms that grow deciduous bonsai. 

Could anyone with extensive knowledge of the professional bonsai scene in Japan help me locate these?

Many thanks this is a great resource:)

In matters of deciduous trees, I would really like to visit Master Toyoda's Nursery, in Kawaguchi, Saitama...

You can find it by searching for "Bonsai Fukujuen", his Zelkovas are amazing!

I would also try to visit the "BonsaiQ" nursery from the YT channel, I think it's "Toju-en Bonsai" also in Saitama.

If you'll pass by Saitama, there's also the Omiya Museum...

Oh, and also I would really enjoy to visit Ebihara's Garden, His Maples and techniques are amazing, and I know it's outside Tokyo, but I'm not sure where, couldn't find it on Google maps... I know Jonas Dupuich visited him years ago, maybe him or Oscar can tell you better.


EDIT:
I don't have extensive knowledge of the professional bonsai scene in Japan, just mentioning artists I admire, and if you pass by, they'll probably have another Bonsai Villages to point you.