Boils down to the basics of proper science - how does one measure/quantify close friends?
I think this one is interesting. If you saw them daily for 20 years and then transitioned to once a year are they automatically not close friends? Even if they satisfied the other criteria (like you could turn to them when you are facing a serious problem, you have deep conversations on that annual meeting because you are comfortable with them, etc)?
The term 'close' friend at least to me means close. Either in physicality or depth and regularity of contact.
Only talking to them once a year, even in depth is more like a semi-close friend. They are not there to help you with the day to day issues that you may not even realize you're having.
That's my criteria anyways...