Refer to Diagonals

Is the diagonal between a6 and f1 the a6-f1 diagonal (alphabetical order) or the f1-a6 diagonal (numerical order)?

Here is a reference listed in another Chess.com thread. Looks like the convention seems to be "left to right". So in your example, it would be "a6-f1" diagonal.

I just found an online reference to standard diagonal notation:

http://www.mark-weeks.com/aboutcom/ble21brd.htm

"The diagonals are often referred to by their starting and ending squares, from left to right. The 'a1 to h8' and 'a8 to h1' diagonals are the longest on the board, eight squares each."

Kewl. Thanks!

I tend to name them relative to the side that is on the move.

So for White, that's the f1-a6 diagonal, while for Black it's the a6-f1 diagonal.

Kewl too. Thanks also. I wasn't sure if there was agreement on how to do this (don't want the cool kids to make fun of me).