This lens had some defects, was $15 @2015.

This lens was said as the same as C/Y Planar 50mmF/1.7,
though not sure of it myself, Tomioka made it definitely.
That is why I bought it, for curious and challenging to fix
the defects (mainly the focus is way off yet can reach Inf).

I think it looks more like Yashical ML 50mmF/1.7, the size
of lens openings are almost same, but ML one is heavier.