Roboku Español

Puzzles › Case 34

Case 34: who took the Illuminated Book?

Difficulty: ★★★★★ · Board 9×9 · 8 suspects

The guard on duty at the library admits, a little embarrassed, that he dozed off for ten minutes. When he woke up, the Illuminated Book, resting in the Lobby, was gone. He swears he doesn't snore that loudly. Help the police unmask the thief.

The board

ABCDEFGHI123456789ShelfSeatScreenPlantTable123456789101112

Suspects and clues

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
  1. Tariq's clue: He's 5 rows away from the Archive. It leaves a single cell: B2.
  2. Wendy's clue: She's in row 7 and next to a wall. 6 cells remain possible: A7, B7, C7, D7, F7 and I7.
  3. Kenji's clue: He's next to a seat. 2 cells remain possible: F2 and E3.
  4. Sven's clue: He's not in the Reading Room. 61 cells remain possible.
  5. Yusuf's clue: He's in the Reception Area. 3 cells remain possible: C8, B9 and C9.
  6. Dana's clue: She's in column H. 9 cells remain possible.
  7. Nadia's clue: She's in the Lobby. 4 cells remain possible: C6, D6, C7 and D7.
  8. Matthew's clue: He's 2 columns away from the Reception Area. It leaves a single cell: A8.
  9. The stolen item's clue: It's right next to the Study Room. 8 cells remain possible.
  10. Tariq can only be on B2. No one else can be in row 2 or column B, and no other character can be in the Storage Room.
  11. F2 has already been ruled out, so Kenji can only be on E3. No one else can be in row 3 or column E, and no other character can be in the Restrooms.
  12. Matthew can only be on A8. No one else can be in row 8 or column A, and no other character can be in the Vault.
  13. C8 and B9 have already been ruled out, so Yusuf can only be on C9. No one else can be in row 9 or column C, and no other character can be in the Reception Area.
  14. Every cell still open to Wendy is in row 7, so no one else can be in that row.
  15. C6, C7 and D7 have already been ruled out, so Nadia can only be on D6. No one else can be in row 6 or column D, and no other character can be in the Lobby.
  16. There are as many suspects (counting the item) as columns, so each column holds exactly one. Only Wendy can still reach column F, so that is where she must be.
  17. A7, B7, C7, D7 and I7 have already been ruled out, so Wendy can only be on F7. No one else can be in row 7 or column F, and no other character can be in the Café.
  18. There are as many suspects (counting the item) as rows, so each row holds exactly one. Only Dana can still reach row 5, so that is where she must be.
  19. H1, H2, H3, H4, H6, H7, H8 and H9 have already been ruled out, so Dana can only be on H5. No one else can be in row 5 or column H, and no other character can be in the Reading Room.
  20. There are as many suspects (counting the item) as rows, so each row holds exactly one. Only the Illuminated Book can still reach row 4, so that is where it must be.
  21. G1, F2, G2, H2, F3, G3 and H3 have already been ruled out, so the Illuminated Book can only be on G4. No one else can be in row 4 or column G.
  22. Every other cell the clue allowed has already been ruled out, so Sven can only be on I1.

Conclusion: Dana is the only person sharing the Reading Room with the Illuminated Book, which is on G4. She is the thief.

ABCDEFGHI123456789ShelfSeatScreenPlantTable123456789101112TWKSYDNMI

Enjoyed it?

The app has hundreds of cases like this one, a new challenge every day and hints when you get stuck. It's free in your browser, on iPhone and on Android.

Play for freeApp StoreGoogle Play