Hello world! Discovered how to find out the hidden date of birth in the wk completely by accident.
This is done through search.
First, you need to find the right person with a hidden date of birth in the search:
Now you need to go down the filter and unwrap the "Extra" tab:

Then we start to go through the first day, until the right person appears in the search.
When the right person appears in the search, we begin to sort through the month, and then the year.
As a result, we get the date of birth in the search itself.

That's the simple way you can get a hidden date of birth of a man VKontakte, which he hid.