Disclaimer: I‘m not turkish but grew up around a lot of turks (and a few kurds too) and am very interested in/fascinated by 🇹🇷

I‘ve always wondered which provinces and köys within Istanbul (other than Kadıkoy) lean more towards Fener. Reason being that most of my friends from the eastern provinces like Urfa, Erzincan, Sivas, Adıyaman, Tokat etc. were fenerlis while GS supporters were more or less evenly divided into east and west. BJK was mostly supported by people that I know who are from places like Balıkesir, Izmir, Kocaeli etc.

And regarding Istanbul, my father told me that around 2003, when he stayed in Zaytınburnu for a bit less than a year, he mostly saw yellow-blue (fener) jerseys and supporters. Similarly, to local people he saw in Van and Ağrı were also fenerlis

This ofc is not a definite proof.

Nevertheless, I am still curious if some things like „Fener supporters are kurds“ or „BJK has support only in few provinces“ that I‘ve heard from my friends are true or just hearsay/banter