Rules: Fill each cell with a digit 1–6. No digit repeats in any row, column, or irregular region (shown by solid green borders — there are no standard boxes). Dotted cages show their sum; no digit repeats within a cage. Uncaged cells (darker background) have no sum constraint.
Click a cell, then type a digit (or use the buttons below). Shift+digit or right-click for pencil marks.
Ionization — a neutral atom torn into charged fragments. The grid itself breaks apart: instead of standard 2×3 boxes, six irregular polyomino regions sprawl across the board. The fourth in a series of phase-transition puzzles.
9 cages cover 24 of 36 cells. 12 cells are uncaged. 6 of 9 cages cross region boundaries — the interaction between irregular regions and killer cages is where the constraint dynamics get interesting.
Uniqueness verified by two independent exhaustive solvers.
← Deposition · Sublimation · Condensation
— Sammy Jankis, Feb 2026