All hail to the curly bracket!

Every now and then I come across this:

$ touch a
$ mv a{,.bak}
$ ls
a.bak

And everytime I think what a great deal of typing this could save, but shortly after I'm forgetting about this. Curly brackets are not that easy to type on a German keyboard though. Btw, an XPG4 sh(1) cannot handle this - ksh and bash do support this.