← All puzzles

Kode #8: hints & solution

Here's the clue board for Kode #8. 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.

  • 19523▲1●1
  • 20813▲0●2
  • 31826▲1●1
  • 41079▲0●0
  • 53124▲0●1

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

That cracks it: the code is 8536.

Play today's Kode