Recently, Sacha Chua wrote about how she leveraged abo-abo’s def-repeat-command to easily call windmove and ace-window. She bound the function to the prefix key-chord of yy. That seemed an odd choice to me but I just shrugged and moved on.
Now it appears that she was on to something. John Cook has a nice post that looks at rare bigrams to use as a key-chord. The idea is that if you choose a rare combination, you’re less likely to activate a key-chord by mistake. As it happens, yy is one of those rare combinations making it a perfect prefix for her window switching commands. I use a QWERTY keyboard so yy has the additional advantage of being easy to type even though it’s not on the home row. I know Chua uses a Dvorak keyboard but that has y in roughly the same place so, again, it’s a win for ease of typing.
I have no idea whether Chua was aware that yy is a rare combination, used her intuition that it wasn’t very likely, or just chose a random key-chord but it turned out to be an excellent choice. If you like using key-chords, take a look at Cook’s post for some ideas on which ones are apt to keep you out of trouble.