Launched as an "abolute amplifier" project in 1978 with the famed Matti Ottala at the helm, the Citation XX landed in the catalogs in 1980 and in a few (rich, very rich) homes at about the same time. You don't see these that often, in fact you never do : just plain mythical.
Accompanied slightly later by a smaller combo (Citation X-I and Citation X-II) which you don't see that often either. In fact you never do.
An optional wooden crate was available for both the XX as well as for the Citation XXP preamp - needless to say : you never see these either !
If the crates bear a "Produced by Harman/Kardon, Woodbury NY USA", the rest, the electronic design was handled by Mr Mamoru Sekiya, at Shin Shirasuna (aka Silver), with the engineering recommendations of Dr Matti Ottala naturally included in the final designs.
Mr Sekiya holds today a senior position at Onkyo.
The Citation XX was orignally prototyped in silver color - much prettier.
The real technical meat is at hand from the two dedicated japanese catalogs but awaits translation from japanese to english, alongwith a 1979 8-page interview with Dr Ottala...