Evil 10×10 Picross — Nested Hypothesis Chains Across 100 Cells
Evil 10×10 Picross is the hardest configuration the benchmark format supports. Clue density is at its maximum, primary hypothesis chains run ten to sixteen steps before resolving, and some configurations require a nested secondary hypothesis within the primary chain's conditional world before the primary assumption can reach a contradiction or confirmation. On a 20-line, 100-cell grid, this structure produces the most analytically demanding solving experience the standard Picross format can generate.
What "Evil" Means at 10×10
Evil 10×10 configurations are designed around three compounding properties that distinguish them from Extreme.
Extended primary chains: Where Extreme cycles run five to ten steps before reaching a contradiction, Evil cycles run ten to sixteen. Each step in the chain modifies the constraint state of one or more of the 20 lines, and the full chain must be tracked accurately before the contradiction can be identified. A single incorrectly applied deduction mid-chain invalidates every subsequent step.
Nested secondary hypotheses: Some Evil configurations produce primary chains that reach an intermediate state — typically around step six to nine — where two or more lines each have exactly two remaining valid arrangements and no direct contradiction is apparent. At this point, a secondary hypothesis must be opened within the primary chain's conditional world: a Level 2 assumption applied to the constraint state that Level 1 has produced. Level 2 must be resolved to a contradiction or confirmation before Level 1 can continue.
Minimal inter-cycle cascade: As at Extreme difficulty, each confirmed hypothesis cell unlocks very few direct deductions before the grid exhausts again. Evil configurations ensure that the total cycle count remains high and that each cycle must be executed at full precision without the recovery margin that larger cascades would provide.
The Evil 10×10 Solving Approach
Complete standard exhaustion: Apply all standard methods fully. On Evil 10×10, this phase typically resolves 55–70 cells. Document the resulting grid state precisely — this is the baseline to which any failed primary hypothesis cycle must restore the grid.
Primary hypothesis construction: Select the line with minimum remaining valid arrangements. Assume the first arrangement. Begin documenting the Level 1 chain sequentially. Apply each consequence to the constraint state of all 20 lines before recording the next deduction.
Secondary hypothesis management: When the Level 1 chain reaches an ambiguous state requiring a nested test, open Level 2 clearly marked in the documentation. Apply Level 2 deductions separately from Level 1. Resolve Level 2 — find its contradiction or confirmation — then use that result to continue the Level 1 chain. When Level 2 is resolved by contradiction, unwind only Level 2 marks. When Level 1 ultimately resolves by contradiction, unwind all Level 2 marks (if any remain) first, then all Level 1 marks.
Post-cycle processing: After each complete primary cycle, apply the full standard method sequence. Even Evil configurations occasionally produce a small post-cycle cascade — extract it fully before opening the next primary cycle.
Evil 10×10 in the Full Difficulty Progression
Evil 10×10 represents the most demanding single-format test the platform's benchmark grid can offer. Solvers who reach this level have typically worked through the full 10×10 difficulty spectrum and have built hypothesis cycle management into a reliable process rather than an occasional technique.
The nested hypothesis framework developed at Evil 10×10 scales directly to larger grid sizes. Evil 12×12, Evil 15×15, and above use the same primary and secondary hypothesis structure across larger constraint networks with proportionally longer chains. Evil 10×10 is the most efficient grid at which to establish the full two-level hypothesis discipline before applying it to grids where individual sessions extend to several hours.
→ 12×12 Evil — nested hypothesis across a 24-line, 144-cell network
→ 15×15 Evil — extended Evil sessions across 225 cells
→ 10×10 Extreme — if Evil feels premature, Extreme builds the sustained multi-cycle discipline Evil requires
Stuck? At Evil, the 10×10 Solver is most valuable as a post-cycle analytical tool. After each primary cycle, compare the solver's chain length, hypothesis selection, and Level 2 entry point to your own — the divergence points identify specific gaps in technique more precisely than reviewing the grid state alone.
FAQ
Most solvers with solid Extreme fluency take 70–120 minutes. Evil 10×10 is a multi-hour session for many players — not because any individual cycle is intractable, but because the total number of cycles, the length of each primary chain, and the occasional nested secondary hypothesis accumulate into a sustained analytical undertaking. Approaching it across two dedicated sessions is completely reasonable.
Evil 5×5, 6×6, and 8×8 have higher per-cell difficulty — tighter constraint networks where errors propagate immediately — but shorter individual chains and smaller total solving loads. Evil 10×10 has longer primary chains, larger constraint networks, and substantially greater total session length. Most solvers find Evil 10×10 harder in total; many find the smaller Evil sizes more intense in any given moment.
Completing 10×10 Extreme without solver assistance across multiple puzzles. Extreme at 10×10 builds the specific combination of skills Evil requires: multi-cycle documentation discipline, reliable standard exhaustion before each hypothesis, clean unwinds, and post-cycle cascade extraction. Attempting Evil 10×10 without established Extreme fluency at the same grid size typically produces sessions that begin cleanly and collapse at the first nested secondary hypothesis.
Yes, for the large majority of solvers. Primary chains of ten to sixteen steps, with intermittent Level 2 branches, across a 20-line grid cannot be reliably tracked without written records. The specific notation format is flexible, but it must clearly distinguish Level 1 deductions from Level 2 deductions and support selective undo at each level independently.