SPOILER ALERT I don't know about "hardest" but I do tend to wonder: who'd have thought to promote to anything other than one's own color? Kinda feels similar t

SPOILER ALERT I don't know about "hardest" but I do tend to wonder: who'd have thought to promote to anything other than one's own color? Kinda feels similar to doing some odd operation "in a single processor instruction" but the trick is that the ISA in question went the way of the dodo about four decades ago.