Excuse please Andrew, but your Minerva is not from 1050th, nore from 1970th, it is a re-assempled of the middle of 1980th with a Wakmann caliber Valjoux 730 upcraded to a Valjoux 88.8. Because this the name "Wakmann" on the bridge is reamed. After the end of produktion of Wakmmann swiss, there were