Sudoku and Sujiko are both grid-based logic puzzles you solve by pure deduction, so solvers naturally wonder how alike they really are. The short answer: Sujiko is close 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: 3×3
- Closeness to Sudoku: Close
What is Sujiko?
A 3×3 grid filled with 1–9 where four circled numbers give the sum of the four cells around each inner corner. Here are the rules in full:
- Place the digits 1–9, each once, in the nine cells.
- Each of the four circles sits at an inner corner and equals the sum of the four cells touching it.
- Those four overlapping sums pin down the whole grid.
See a Sujiko grid
Sujiko fills a 3×3 grid with 1–9, and a circle at each inner corner gives the sum of the four cells around it. Here the top-left circle reads 12, because the four cells it touches (1, 2, 4, 5) add to 12.
The circle (12) is the sum of its four surrounding cells: 1 + 2 + 4 + 5.
Those overlapping four-cell sums are Killer Sudoku shrunk to nine cells — the same "which digits add to this?" reasoning as a Killer cage, just without any rows, columns or boxes to worry about.
What Sujiko shares with Sudoku
- The "distinct digits plus a sum clue" idea is exactly Killer Sudoku in miniature.
- Working out which digits hit each circle is the same combination reasoning Killer needs.
How Sujiko differs from Sudoku
- It is a single 3×3, so there are no rows, columns or boxes to satisfy — only the four corner sums.
- Every digit 1–9 is used once across the whole grid, not once per line.
- And it is tiny — nine cells against Sudoku's eighty-one — so a Sujiko is solved in a minute, not a sitting.
Do Sudoku skills transfer?
Sujiko is a bite-sized workout for the same combination skill Killer Sudoku demands: which four distinct digits add to this circle? Solve a few and Killer cages feel easier.
Brush up on the technique that carries over: Killer Combinations.
The verdict
Sujiko is a pocket-sized Killer Sudoku — four overlapping sums on nine cells, same combination logic.
Prefer to stay with Sudoku?
If Sujiko appeals, these Sudoku variants scratch the same itch and you can read up on each here: