I collect antique Japanese tansu furniture and have a few pieces that
have locks but no key.  I will be travelling to Japan this summer and
wish to find an antique locksmith that might have such keys in stock
or could fashion keys for these pieces.  I would bring the lock
hardware with me.

Hello,

Since no one responded - I would give it a shot.

There are quite a few furniture maker in Kyoto area they do have some
antiques dealer there as well.  The best way to do this is to actually
bring the lock with you and probably leave it with the dealer and they
can send them to people who can actually do it.  It will take time
before you can get back the lock.

PS.  make sure you bring a friend who can speak Japanese to explain
what you want.  If you need help let me know I am about an hour out of
Kyoto.