Kode #66: hints & solution
Here's the clue board for Kode #66. Start with the spoiler-free hints. If you're still stuck, the full step-by-step solution is below, hidden until you open it.
The clue board
Each row is a guess that's already been graded. ▲ means a right digit in the right spot; ● means a right digit in the wrong spot.
- 12190▲1●1
- 22139▲0●2
- 33062▲0●2
- 44073▲0●3
- 59827▲0●0
Spoiler-free hints
- 2 of the four digits are even.
- The four digits add up to 8.
- Every digit is below 5.
Try the hints first. The solution below walks through every deduction.
Step-by-step solution
Every Kode can be cracked by pure deduction, with no guessing. This board falls in 10 logical steps. Open the solution to follow them one at a time.
Show the solution · reveals the code
When a row "rules out" a position, it shows that digit there but its ▲ marks are already used up (or it has none), so the digit can't sit there.
- Row 5 (9 8 2 7) has no marks at all, so 9, 8, 2, and 7 are not in the code.
- Row 1 (2 1 9 0) has 2 marks still unexplained, and only 2 digits are left undecided: 1 and 0. So both are in the code.
- Row 2 (2 1 3 9) has one mark still unexplained, and only one digit is left undecided: 3. So it is in the code.
- Row 3 (3 0 6 2) has 2 marks, already accounted for by 3 and 0. That rules out 6.
- Row 4 (4 0 7 3) has one mark still unexplained, and only one digit is left undecided: 4. So it is in the code.
- That makes all four digits of the code: 0, 1, 3, and 4. Every other digit is out, which also rules out 5.
- Row 1 (2 1 9 0) has one digit in the right spot. Since row 2 rules out the 1 in position 2, it has to be the 0 in position 4.
- The 3 has only one spot left: position 2 (row 3 rules out position 1, row 2 rules out position 3, and position 4 is already 0).
- The 4 has only one spot left: position 3 (row 4 rules out position 1, position 2 is already 3, and position 4 is already 0).
- That leaves the 1 for position 1.
That cracks it: the code is 1340.