Roboku
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Case 20: who took the Pocket Watch?
During last night's private gala at the museum, a guest must have gotten a little too close to the Pocket Watch, on display in the Restoration Room, because it was gone by morning. The guest list is short; so is the room for error. Help the police unmask the thief.
The board
- 1Lobby
- 2Café
- 3Office
- 4Storage Room
- 5Reception Area
- 6Archive
- 7Restoration Room
- 8Security Room
- Plant: no character can stand on its cell, but the stolen item can be there.
- Seat: anyone can be on it.
- Table: nothing can be on its cell.
- Screen: nothing can be on its cell.
- Window: the blue line on a wall.
Suspects and clues
- CChidi
He's next to a wall. - IIvan
He's not in the Security Room, and he's in row 1. - OOmar
He's next to a window. - KKenji
He's next to a plant. - GGrace
She's in column F and right next to the Office. - ZZara
She's in the Reception Area and 1 column away from the Restoration Room. - PPocket Watch (stolen item)
It's 5 rows away from the Lobby.
Remember the rules: no two suspects (nor the item) ever share a row or a column, each character is in a different room, and the thief is the only one sharing a room with the stolen item. Unsure? Read how to play and the clue types.
Solution
Try it yourself first: pen and paper are enough. When you want to check, open the reasoned solution.
Show the step-by-step solution
- Chidi's clue: He's next to a wall. 43 cells remain possible.
- Ivan's clue: He's not in the Security Room, and he's in row 1. 6 cells remain possible: A1, B1, C1, D1, E1 and G1.
- Omar's clue: He's next to a window. 4 cells remain possible: F1, A4, G4 and E5.
- Kenji's clue: He's next to a plant. 2 cells remain possible: A5 and A7.
- Grace's clue: She's in column F and right next to the Office. 3 cells remain possible: F1, F2 and F3.
- Zara's clue: She's in the Reception Area and 1 column away from the Restoration Room. It leaves a single cell: E3.
- The stolen item's clue: It's 5 rows away from the Lobby. It leaves a single cell: B7.
- Zara can only be on E3. No one else can be in row 3 or column E, and no other character can be in the Reception Area.
- The Pocket Watch can only be on B7. No one else can be in row 7 or column B.
- A7 has already been ruled out, so Kenji can only be on A5. No one else can be in row 5 or column A, and no other character can be in the Lobby.
- There are as many suspects (counting the item) as rows, so each row holds exactly one. Only Chidi can still reach row 6, so that is where he must be.
- There are as many suspects (counting the item) as rows, so each row holds exactly one. Only Grace can still reach row 2, so that is where she must be.
- F1 and F3 have already been ruled out, so Grace can only be on F2. No one else can be in row 2 or column F, and no other character can be in the Security Room.
- F1, A4 and E5 have already been ruled out, so Omar can only be on G4. No one else can be in row 4 or column G, and no other character can be in the Restoration Room.
- Every other cell the clue allowed has already been ruled out, so Chidi can only be on C6. No one else can be in row 6 or column C, and no other character can be in the Storage Room.
- A1, B1, C1, E1 and G1 have already been ruled out, so Ivan can only be on D1.
Conclusion: Chidi is the only person sharing the Storage Room with the Pocket Watch, which is on B7. He is the thief.