It strikes me as a kind of modularisation. There's a constraint on the solution that involves dozens of rows, columns and boxes in combination; but you can trea

It strikes me as a kind of modularisation. There's a constraint on the solution that involves dozens of rows, columns and boxes in combination; but you can treat combinations of that style as a reusable module, like "center ring and corners". I'm not sure that's an accurate way of thinking of it, but if so it would make it similar to Rubik's Cube moves, where you string dozens of individual low-level moves together to build the desired effect. Edit to add: hmm, thinking about it, many Cube moves have the form A-B-A', where you get into position with A, apply the key move B, then back out of A again. The Sudoku equivalent might be applying a grid permutation A that preserves the constraints, solving cell B, then backing out of A again. But that's probably not a convenient way for human solvers to think about it, as you can't physically permute a Sudoku like you can with a Cube.