The lens does not mount the distance marker at the top, probably my PK->EF adapter is not well made(?), the aperture linkage lever is
at the top in this situation, which is the worst position of the lever. That is why I had to cut the lever, in case you do not have to cut it
if your adapter mounts the lens other way around, though hard to use. The lettering of this lens is almost identical to Yashica ML lens'.

Topic: Also there are Rikenon version 55mmF/1.2 lenses, the first Rikenon 55mmF/1.2 (M42 mount) was Tomioka made, the later
XR Rikenon 55mmF/1.2 and Rikenon P 55mmF/1.2 were made by Cosina, this is generally known. Unlike PORST versions, these
lenses were copied from the original Auto Yashinon DM-S 55mmF/1.2 optical design, but later re-designed and made by Cosina.
Of course Yashica ML 55mmF/1.2 was designed based upon this same Auto Yashinon DS-M 55mmF/1.2 without rear element cut.