If you enjoy Killer Sudoku because of its cage arithmetic and candidate elimination, PUZRU should feel immediately understandable. Connected cells have target sums, and combinations must fit the surrounding row and column constraints.
What feels familiar
- Cage totals restrict which digit combinations can fit.
- High and low totals can create strong early deductions.
- Arithmetic becomes more powerful when crossed with placement restrictions.
What is different from Killer Sudoku?
PUZRU is not Sudoku. The board is 6×6, uses the digits 1–6, and has no 3×3 box rule. Every row and column must contain 1–6 once. On top of that, the puzzle is part of a real-time global Chain: one Discoverer finds the puzzle first and six solved cells carry forward.
Why the smaller grid matters
The compact format makes chained deductions visible quickly and works naturally on mobile screens. The challenge comes from how cage sums interact with row and column uniqueness, not from filling a larger number of cells.
What changes in practice?
Put the idea into practice
The fastest way to understand the interaction between row, column and cage constraints is to solve a board. Start in the 200-puzzle progressive Training Room, then enter the live world whenever you are ready to race for Discoverer.