Recently I was browsing old issues of my clubzine when I tripped over "IGM". Wait, aren't all Grandmasters international by default? But I'm old enough to remember that the abbreviation "IGM" instead of the now-familiar "GM" was actually in use decades ago (1970ish).
- Was there ever a difference between GM and IGM (obviously, let's restrict to the official FIDE period 1950+)? I assume not.
- If it was just a matter of standard abbreviation — when did it change? (Educated guess on the why: computer tables.)