Kode #9: hints & solution
Here's the clue board for Kode #9. 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.
- 14687▲1●1
- 24517▲0●1
- 34693▲0●2
- 49271▲0●0
- 58126▲0●2
Spoiler-free hints
- 2 of the four digits are even.
- The four digits add up to 22.
- 3 of the digits are 5 or higher.
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 4 (9 2 7 1) has no marks at all, so 9, 2, 7, and 1 are not in the code.
- Row 5 (8 1 2 6) has 2 marks still unexplained, and only 2 digits are left undecided: 8 and 6. So both are in the code.
- Row 1 (4 6 8 7) has 2 marks, already accounted for by 6 and 8. That rules out 4.
- Row 2 (4 5 1 7) has one mark still unexplained, and only one digit is left undecided: 5. So it is in the code.
- Row 3 (4 6 9 3) has one mark still unexplained, and only one digit is left undecided: 3. So it is in the code.
- That makes all four digits of the code: 3, 5, 6, and 8. Every other digit is out, which also rules out 0.
- Row 1 (4 6 8 7) has one digit in the right spot. Since row 3 rules out the 6 in position 2, it has to be the 8 in position 3.
- The 6 has only one spot left: position 1 (row 3 rules out position 2, row 5 rules out position 4, and position 3 is already 8).
- The 3 has only one spot left: position 2 (row 3 rules out position 4, position 1 is already 6, and position 3 is already 8).
- That leaves the 5 for position 4.
That cracks it: the code is 6385.