how a good name can make a big difference in the quality of the code
No. The players say,
Oh, look, I had four yellow tokens in a row back there ten moves ago.
You do not need to go through all the board to look for a winning move. You need to look at the most recently‑placed token and see whether that is a winning token. So you need to look left right down and diagonally to SE and SW. All your checking of rows and columns is unnecessary: only sixteen locations need to be checked.
I have just put my yellow token to make a row of four here: I win