1971 Original MYU 701

"The first Murex appeared in 1971, and was called the "MYU 701" in Japanese and identified by the Greek letter for "m" in Pilot's advertisements. Its model number is M-350SS. "

Mine would be a mar 1976 make with F nib given the engraving H376.

source: http://stutler.cc/pens/murex/index.html