Printable Hell Sudoku PDF (Forcing Chains)

Updated 6 October 2026

Every puzzle in this booklet needs a forcing chain: none can be finished with the techniques Nightmare allows, and each is drawn from our bundled and independently verified Hell corpus rather than generated fresh. Our published sample of 40 boards measures the tier at SE 7.6 to 8.1, with the Nishio Forcing Chain as the most common hardest step. See the 17-clue guide for why the clue count is not what makes them hard.

What is inside the booklet

Some of these grids start with as few as 17 givens and look almost empty at first glance — the 16 puzzles print 4 to a page with generous cell size specifically so there is room to track candidates by hand across a long chain. The final pages hold the completed grids, which is close to essential at this tier: verifying a chain of eliminations by eye is slow, and a printed key lets you confirm the end state without re-deriving the whole path.

How the puzzles are verified

Every puzzle in this booklet comes from a bundled corpus that Suuudokuuu checks with two independent solving algorithms — a Dancing Links exact-cover solver and a typed-array bitmask solver — before it ships, so each grid is confirmed to have exactly one solution. The corpus draws from the tdoku project’s 17-clue catalog and the magictour top1465 hard-puzzle list, and each puzzle is also solved logically and rated on the SE scale as the corpus is packed. Only boards whose hardest step is a forcing chain survive; anything that falls to a chain, coloring or AIC is dropped, because neither the clue count nor the source list alone would be enough to promise a Hell puzzle. Every survivor still solves on our technique ladder without guessing, so every puzzle here is guaranteed solvable by logic before you ever pick up a pencil.

Where to go next

Not ready for chains on paper yet? Step back to the printable Nightmare sudoku booklet for the same chain reasoning with more of the grid filled in, or to printable Hard sudoku for fish and wings without chain-length reasoning, or play Hell on a screen at the Hell sudoku lander, where the same corpus powers every puzzle. Ready for the record puzzles? The printable Infinity sudoku booklet prints Everest, AI Escargot and other record grids.