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Kode #67: hints & solution

Here's the clue board for Kode #67. 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.

  • 14978▲1●1
  • 25671▲0●2
  • 34697▲0●1
  • 49850▲1●1
  • 59276▲0●0

Spoiler-free hints

  • 2 of the four digits are even.
  • The four digits add up to 18.
  • 2 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 9 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.

  1. Row 5 (9 2 7 6) has no marks at all, so 9, 2, 7, and 6 are not in the code.
  2. Row 1 (4 9 7 8) has 2 marks still unexplained, and only 2 digits are left undecided: 4 and 8. So both are in the code.
  3. Row 2 (5 6 7 1) has 2 marks still unexplained, and only 2 digits are left undecided: 5 and 1. So both are in the code.
  4. Row 4 (9 8 5 0) has 2 marks, already accounted for by 8 and 5. That rules out 0.
  5. That makes all four digits of the code: 1, 4, 5, and 8. Every other digit is out, which also rules out 3.
  6. Row 1 (4 9 7 8) has one digit in the right spot. Since row 3 rules out the 4 in position 1, it has to be the 8 in position 4.
  7. Row 4 (9 8 5 0) has one digit in the right spot. Since the 8 is already in position 4, it has to be the 5 in position 3.
  8. The 4 has only one spot left: position 2 (row 3 rules out position 1, position 3 is already 5, and position 4 is already 8).
  9. That leaves the 1 for position 1.

That cracks it: the code is 1458.

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