Da Dao Translation & Info Requested

[RobT]

Ren Ren,

I see that my photos were taken upside down. Many thanks for giving me what is legible thus far. It fits with what I had hoped for because it strengthens my suspicion that the sword is of Chinese Communist manufacture and, as such, probably dates from somewhere around the second Sino Japanese war. I will see if I can get better photos for a full translation.

Sincerely,
RobT