Frame Sudoku: A hybrid between Killer Sudoku and Outside Sudoku

Abandon standard internal clue placement. Engineered specifically for advanced solvers requiring a rigorous transition in deductive strategy, this volume introduces a strict mathematical hybrid of perimeter tracking and spatial exclusion. [Image of a Frame Sudoku puzzle grid with external sum clues] The internal 81-cell matrix is entirely empty. All clues are shunted to the external perimeter, functioning as arithmetic sums...