Who made Curtis Mathis Japanese 6BQ5?

[kctx2]

Were they an American subcontract? I assume Curtis Mathis tubes were made in the late 60's. Any info on quality etc? The newer foriegn tubes have some reliability issues, but I am guessing the late 60's foriegn made tubes would be of decent quality.
Any input???

[rockon1]

Pics?

[chaz]

The few Japanese tubes I've seen were Matsushito(hope I didn't butcher the name) and were very good tubes!