Sudoku and Inshi no Heya are both grid-based logic puzzles you solve by pure deduction, so solvers naturally wonder how alike they really are. The short answer: Inshi no Heya is very 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: n×n Latin, rooms
- Closeness to Sudoku: Very Close
- Also called: Room Product, Product Rooms
What is Inshi no Heya?
A Latin-square grid split into rooms, each printed with the product its cells must multiply to — the puzzle that inspired KenKen. Here are the rules in full:
- Fill an n×n grid so each row and column holds 1–n exactly once.
- Each room shows a number equal to the product of the digits inside it.
- A digit may repeat inside a room, provided the row/column rule holds.
See an Inshi no Heya cage
Inshi no Heya is a Latin square split into rooms, each printed with the product its cells must multiply to. Here a two-cell room marked "12" holds 3 and 4, since 3 × 4 = 12.
An Inshi no Heya board: each coloured room shows the product its digits must multiply to. Fill 1–4 in every row and column — the "12" room here holds 3 and 4.
It is the direct ancestor of KenKen, and a multiplication cousin of Killer Sudoku: the Latin-square rule is Sudoku's core, and factoring a product ("which digits make 12?") is exactly Killer's combination logic — you just multiply instead of add.
What Inshi no Heya shares with Sudoku
- The Latin-square rule — each digit once per row and column — is Sudoku's core.
- Rooms with arithmetic targets are the idea behind Killer and Calcudoku.
- Listing which digits multiply to a target is combination analysis, just as in Killer.
How Inshi no Heya differs from Sudoku
- Clues are products, not sums, and there are no boxes.
- A digit can repeat within a room, which Killer cages forbid.
Do Sudoku skills transfer?
Killer's combination skill transfers straight across — you just factor instead of add. "Which digits multiply to 12 in two cells?" is the same hunt as a Killer sum.
Brush up on the technique that carries over: Killer Combinations.
The verdict
Inshi no Heya is a multiplication cousin of Killer Sudoku on a Latin square — KenKen's direct ancestor.
Prefer to stay with Sudoku?
If Inshi no Heya appeals, these Sudoku variants scratch the same itch and you can read up on each here: