oren wrote:No, I know the Nihon Kiin owns the building, but I do not know what the contract details are.
Thank you, oren. Like you, I also don't know the contract details -- which may be relevant.
oren wrote:The bank owns my house, but I would certainly sue them if they kicked me out to claim ownership.
A real estate company owns the building my company leases, and they will get sued if they breach the lease.
Seems to me these two analogies are not good here.
The bank and the real estate company are not offering help
to you --
they are trying to make a profit
from you (a business transaction).
They did not "let" you stay in the house or the company building "for free" for SIXTEEN+ years.
The following are my
feelings (oren, emphasis on "feelings"; I don't know the facts

):
Iwamoto Sensei and the Nihon Kiin founded the NYGC and SGC --
Iwamoto Sensei and the Nihon Kiin helped to promote Go all these years.
They asked for nothing in return. They just wanted to promote Go.
It is not a "business transaction". They did it entirely out of good will.
(As mentioned earlier, they did similar to help re-build Go in China in the 1980's.)
They donated/funded the NYGC and SGC (and many other Go centers around the world).
Without Iwamoto Sensei and the Nihon Kiin, there would not have been the NYGC and SGC.
The SGC should be thankful for their help all these years.
This is why their honte reply is "Thank you." This lawsuit is extremely bad form.
Let's see if more details emerge. My gut feelings stand.