Double Samurai Sudoku Harakiri: 81 overlapping sudoku puzzles, 8 grids in 1

Abandon standard single-grid isolation and the limitations of basic 5-grid Samurai layouts. Engineered strictly for elite solvers who require a massive escalation in deductive endurance, this collection introduces the Gattai-8 Harakiri architecture. Developed by the regular Samurai Sudoku contributor for the Washington Post, these 81 puzzles provide twice the deductive complexity of standard overlapping volumes by forcing continu...