ZEN cartridge ?

Jorsan...I found this link. You need to scroll down the page a little to see the ZEN cartridge picture.

It is indeed a Sato Musen!

Great detective work.

Here are the translated specs:

Price \ 59,000
■ power generation method MC type
■ output voltage 0.2 mV (5 cm / sec 1 kHz)
■ needle pressure 1.7 g ~ 2.2 g
■ reproduction frequency band 20-20,000Hz
■ Channel separation 27 dB (1 kHz)
■ channel balance　
■ compliance 8 × 10 -6 cm / dyne
■ load resistance 30 ohms
■ load capacity　
■ internal impedance 30 ohms
■ needlepoint 0.6 mil
■ own weight 10g
■ exchange needle actual item exchange (\ 39,500)
■ released 1981
■ discontinued 1988-89 circa
■ remarks price 1981 those of circa
sapphire cantilever adoption.

Prof. Hiroaki Hibino, a long time user of Klipsch speakers,
was not satisfy with the dynamic performance of the regular
carts and designed his own. He demonstrated his cart to Paul
Klipsch who was so impressed that he ordered 4 (?)models
with different cantilevers to satisfy different subjective
preferences. Those are known(?) as 'Klipsch MCZ -' carts.
Later on Hibino produced 'the same' cart under his own brand
name 'Zenn MCZ'. If I remember well the cantilevers were:
aluminium, boron, sapphire and diamond. I own the Klipsch
MCZ-2 with aluminium cantilever.