It has been several years, but I recall a specific move that involves the king and rook on the back row, when no night or bishop is in the way, that a transposition of those two pieces can happen, called a castle. It’s the only move that allows the king to move more than one space, I think I’m remembering correctly!
Post 3329 from this morning’s thread has a definition of Castle Rock move.
WWG1WGA 🇺🇸