Sudoku and Kakurasu are both grid-based logic puzzles you solve by pure deduction, so solvers naturally wonder how alike they really are. The short answer: Kakurasu 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: Square, weighted
- Closeness to Sudoku: Moderate
- Also called: Index Sums
What is Kakurasu?
Shade cells so that the weights of the shaded cells add up to the clue at the end of every row and column. Here are the rules in full:
- Columns are weighted 1, 2, 3… from the left and rows 1, 2, 3… from the top.
- Shade cells so each row's shaded column-weights sum to its right-hand clue.
- At the same time, each column's shaded row-weights sum to its bottom clue.
What a Kakurasu looks like
Kakurasu weights the columns 1, 2, 3… from the left and the rows likewise; you shade cells so each row's and column's shaded weights add to its clue. Here is a small solved grid, with the weight labels around the edge and the clues in the corner cells.
Shaded cells (dark) meet the row and column clues (=1, =2) via their column and row weights.
Reaching a target from a set of distinct weights is the same combination reasoning a Killer cage needs. But you shade cells rather than place digits, and there is no no-repeat rule - only the weight sums. A moderate relative.
What Kakurasu shares with Sudoku
- Reaching a target from a set of distinct weights is the same combination reasoning Killer needs.
- It is a single-solution logic puzzle with no guessing.
How Kakurasu differs from Sudoku
- You shade cells rather than place digits; the grid ends up black-and-white.
- There is no row/column no-repeat rule - only the weight sums.
Do Sudoku skills transfer?
No technique transfers cell-for-cell, but "which distinct weights add to this clue?" is exactly the combination hunt behind Killer cages.
The verdict
Kakurasu is a shading puzzle driven by sum combinations - Killer's arithmetic instinct without the digit placement.
Where to play it
If it was Sudoku you came for, the level is the choice that matters more than the variant - Kakurasu 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.