--- title: Can You Solve This Puzzle Without Guessing? | Zorse Blog description: Four lanterns, sixteen squares, and a small deduction that opens the board. Try a real Yodoku puzzle, then follow the logic one lantern at a time. canonical: https://zorse.io/blog/can-you-solve-this-puzzle-without-guessing last-updated: 2026-10-27 --- # Can You Solve This Puzzle Without Guessing? 1. [Blog](https://zorse.io/blog) 2. Can You Solve This Puzzle Without Guessing? Devlog By [Austin Greco](https://zorse.io/about) · October 26, 2026 · Updated October 27, 2026 [Try the puzzle](https://zorse.io/blog/can-you-solve-this-puzzle-without-guessing#yodoku-puzzle) ![Rounded coral, yellow, mint, blue, and lavender Yodoku tiles surround a glowing golden light on a dark plum background](https://zorse.io/assets/yodoku-no-guess-hero.Bo0mZ5Eu_snhtP.webp) I started Yodoku with the idea of a simplified Sudoku: keep the row, column and region logic, and use lanterns instead of digits. Try this little garden before opening the walkthrough. ![An empty four-by-four Yodoku puzzle. Row 1: yellow B, red A, red A, green C. Row 2: yellow B, yellow B, yellow B, green C. Row 3: yellow B, green C, green C, green C. Row 4: yellow B, blue D, green C, green C.](https://zorse.io/assets/yodoku-no-guess/puzzle-start.456d0892.svg) A real 4×4 Yodoku garden. Numbers identify rows and columns; letters identify colors.
Board description

Four rows and four columns. A is red, B yellow, C green, and D blue. Each letter identifies one connected color region.

  1. Row 1: B, A, A, C.
  2. Row 2: B, B, B, C.
  3. Row 3: B, C, C, C.
  4. Row 4: B, D, C, C.
## The rules - Place exactly one lantern in each color. - Place exactly one lantern in each row and each column. - Lanterns cannot touch, even diagonally. You’ll place four lanterns in total. Letters identify the color regions, and an X can help you keep track of squares you’ve ruled out. Take a moment with the board. Which square gives you a certain start?
Just a hint

Find the color that occupies only one square. Then look at the row immediately above it.

## Familiar logic, different clues [Classic Sudoku](https://www.nikoli.co.jp/en/puzzles/sudoku/) asks you to place each digit once in every row, column and box. Yodoku asks for just one lantern in each row, column and colored region, with one extra constraint: lanterns cannot touch. The question becomes which squares can still hold a lantern. [Minesweeper](https://minesweeper.online/help/gameplay) offers another useful comparison. Its numbers count neighboring mines, helping you eliminate possibilities. In Yodoku, a placed lantern rules out the squares around it. Marking those squares with Xs makes the next deduction easier to see. If you’ve played [Meowdoku](https://play.google.com/store/apps/details?id=com.oakever.meowdoku) or [Zoodoku](https://play.google.com/store/apps/details?id=com.nebula.zoodoku), the row, column and colored-region constraints will feel familiar. Those games place animals; here, you’re lighting a garden. This small board has one solution. Try to explain your next placement before you make it; the walkthrough follows the logic one lantern at a time.
Read the solution walkthrough

One lantern opens the board

1. Start with the blue square.

Blue D has just one square: row 4, column 2. Every color needs a lantern, so that square must have one.

2. Look one row up.

The blue lantern rules out the first three squares in row 3: one directly above it and two touching it diagonally.

Row 3’s lantern must go in its only remaining square: row 3, column 4.

The blue lantern at row 4, column 2 rules out the first three squares in row 3. The remaining square at row 3, column 4 is highlighted.

3. Return to the two red squares.

Red A has two squares in the top row. Blue already uses column 2, so red must go at row 1, column 3.

4. Fill the last row and column.

Row 2 and column 1 are the last without a lantern. They meet at the yellow square at row 2, column 1.

The completed puzzle, with lanterns at row 1 column 3, row 2 column 1, row 3 column 4, and row 4 column 2.

Four lanterns: one in every color, row, and column, with none touching.

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