Haunted Manor is the Halloween puzzle that sits next to the sudoku modes in One Sudoku. It’s quicker to learn than sudoku: there are no digits, just ghosts, and only three rules. If you’ve played a Queens-style or Star Battle puzzle before, you’ll feel at home within a minute.
Like every puzzle in the app, each manor can be solved by logic alone. You never have to guess.
The rules
The manor is a square grid split into coloured rooms. Hide ghosts so that:
- Every floor (row) has exactly one ghost.
- Every hall (column) has exactly one ghost.
- Every room (coloured region) has exactly one ghost.
And one more: no two ghosts may touch, not even diagonally. Every ghost needs all eight of the cells around it to itself.
A grid with six rows has six columns and six rooms, so you hide six ghosts in total.
The habit that solves most of it: cross things out
Every time you place a ghost, three groups of cells are ruled out at once:
- the rest of its row,
- the rest of its column,
- the eight cells around it.
Mark them. In a manor, most of the work is not finding ghosts but deleting the cells where a ghost can’t be. When a row, a column or a room is down to one open cell, that cell is the ghost.
Five ideas worth knowing
1. Small rooms first
A room of one cell is a free ghost. A room of two or three cells is almost as good, because it narrows the options fast. Start every manor by looking at the smallest rooms.
2. A room stuck in one row claims that row
If every open cell of a room lies in the same row, that room’s ghost will be in that row. So the row’s ghost is taken, and every other cell in the row, outside the room, can be crossed out. The same works for columns.
3. Count rooms against rows
The second idea scales up. If two rooms are both confined to the same two rows, those two rows belong to those two rooms. Every cell in those rows that belongs to some other room can be crossed out. Three rooms in three rows works the same way.
It also works backwards: if two rows can only be filled from cells of the same two rooms, then those rooms’ ghosts are in those rows, and the rest of each room can go.
4. Cells that touch a whole room
Look at a small room and ask: is there an outside cell that touches every one of its open cells? If so, a ghost there would leave the room with nowhere to go, so that cell is crossed out. A room that fits inside a 2×2 square knocks out a surprising number of neighbours this way.
5. Try it in your head, not on the board
When a row is down to two cells, picture the ghost in one of them and follow the crossings for a move or two. If some room ends up with no open cells, the ghost belongs in the other one. That’s logic, not guessing: you’ve proved one option impossible.
Three sizes
The manor comes in three sizes:
| Size | Grid | Ghosts |
|---|---|---|
| Cottage | 6×6 | 6 |
| Manor | 8×8 | 8 |
| Castle | 9×9 | 9 |
Bigger grids mean more rooms and longer chains of reasoning, but the ideas above are all you need for every one of them. Start with a Cottage to get the rules into your fingers.
When you get stuck
There’s no timer and no rush. If you stall, a hint points to your next step rather than simply placing a ghost for you, so you learn the move instead of just getting past it.
Haunted Manor is in the app alongside Classic, Killer and Rescue sudoku. If you’d like to try the sudoku side too, Learn Sudoku: A Clear Path from Easy to Expert walks through every technique the app asks of you, in order.
