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Kode #194: hints & solution

Here's the clue board for Kode #194. Start with the spoiler-free hints. If you're still stuck, the full step-by-step solution is below, hidden until you open it.

Play Kode #194

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.

  • 10316▲1●1
  • 20364▲0●2
  • 39528▲0●2
  • 49841▲1●0
  • 53519▲0●0

Spoiler-free hints

  • 4 of the four digits are even.
  • The four digits add up to 16.
  • 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 (3 5 1 9) has no marks at all, so 3, 5, 1, and 9 are not in the code.
  2. Row 1 (0 3 1 6) has 2 marks still unexplained, and only 2 digits are left undecided: 0 and 6. So both are in the code.
  3. Row 2 (0 3 6 4) has 2 marks, already accounted for by 0 and 6. That rules out 4.
  4. Row 3 (9 5 2 8) has 2 marks still unexplained, and only 2 digits are left undecided: 2 and 8. So both are in the code.
  5. That makes all four digits of the code: 0, 2, 6, and 8. Every other digit is out, which also rules out 7.
  6. Row 1 (0 3 1 6) has one digit in the right spot. Since row 2 rules out the 0 in position 1, it has to be the 6 in position 4.
  7. Row 4 (9 8 4 1) has one digit in the right spot, and the 8 in position 2 is its only digit in the code, so it's locked in.
  8. The 0 has only one spot left: position 3 (row 2 rules out position 1, position 2 is already 8, and position 4 is already 6).
  9. That leaves the 2 for position 1.

That cracks it: the code is 2806.

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