I had worked for a company which turned out to be family business. Because I did not want any part in certain business activities, I quit - and surprisingly was even allowed to do so, but of course under obligation to never talk about it.
While I had jobs before and afterwards, this is my only "regular", full-time employment so far and the only employment where I got a certificate of employment (which does not say anything, of course).
I probably cannot leave the time span blank in my CV (can I?), but what do I say when I am asked in an job interview what the firm did and what I did there (without getting shoes or time)?