I'm trying to replace the tires on an old Nitto Japanese postal bike, and I'm having difficulty sourcing tires. No luck on Google or Amazon. I took the bike to a shop that said they could replace them with conventional tires, but they gave up - put the old tires back on and just sold me inter tubes.
On the bike currently are 26 x 1-3/8 tires that fold over each other separating the inter tube from the spoke ends (Type BE??).

Any advice appreciated!

Thanks,
Ken