Sudoku and Ripple Effect are both grid-based logic puzzles you solve by pure deduction, so solvers naturally wonder how alike they really are. The short answer: Ripple Effect is moderate to Sudoku. Below we lay out what the two share, where they part ways, and whether the skills you have built on Sudoku will carry over.
- Grid: Rooms grid
- Closeness to Sudoku: Moderate
- Also called: Hakyuu
What is Ripple Effect?
A grid split into rooms; each room of size m holds 1-m, and equal digits in a line must be spaced at least that many cells apart. Here are the rules in full:
- Each room of m cells is filled with the numbers 1-m, one each.
- If a digit repeats in a row or column, the gap between the two must be at least that digit's value - two 3s need three cells between them.
- Given numbers narrow it to a single solution.
See a Ripple Effect grid
Ripple Effect divides the grid into rooms; a room of m cells holds 1 to m. On top of that, if a digit repeats in a row or column, the gap between the two copies must be at least that digit's value. Below, a three-cell room reads 1, 2, 3.
A Ripple Effect board: each coloured room of m cells holds 1…m (the purple room reads 1-2-3), and where a digit repeats in a line the gap between the copies must be at least that digit's value.
Rooms filled with a fixed run of numbers echo Sudoku's regions and its no-repeat idea, and it is solved by naked singles and elimination - no guessing. The distance rule, where a digit's value sets how far apart repeats must sit, is the one part with no Sudoku parallel.
What Ripple Effect shares with Sudoku
- Rooms filled with a fixed run of numbers echo Sudoku's regions and no-repeat idea.
- It is solved by naked singles and elimination, never guessing.
How Ripple Effect differs from Sudoku
- The spacing rule - distance depends on the digit - has no Sudoku parallel.
- Rooms vary in size, so the number range shifts room to room, and there are no boxes.
Do Sudoku skills transfer?
The room-filling and single-candidate elimination feel familiar; add the distance rule as one more way to rule a digit out, and a Sudoku solver adapts fast.
Brush up on the technique that carries over: Naked Single.
The verdict
Ripple Effect keeps Sudoku's region-filling logic and layers on a distance rule all its own.
Where to play it
If it was Sudoku you came for, the level is the choice that matters more than the variant - Ripple Effect and Sudoku part ways on the rules, but a Sudoku grid can be a two-minute warm-up or an hour of work depending on nothing but how much of it you are given.
Difficulty and type are two separate dials here: the type sets the extra rule, the level sets how much of the grid you start with. Easy Sudoku leaves 36 of the 81 cells filled, so there is always an obvious next move somewhere; Evil Sudoku leaves 23, with no easy moves at all. Take it at the gentler end while the pattern is still new, and move up once it stops being a fight.