Flower Sudoku – Easy

Solve Flower Sudoku: Rules, Overlaps, and Strategies

Flower Sudoku is a multi-sudoku consisting of 5 classic 9×9 sudokus. Five 9×9 sudokus are nested into a compact, flower-shaped figure.

The same grid shape is also called Musketry Sudoku.

The visible figure includes a total of 189 active cells within 15 rows and 15 columns. The central subgrid is fully intertwined with the four outer subgrids. As a result, many cells have more than one sudoku row, column, or block group to consider.

The goal remains familiar: each 9×9 subgrid must have the numbers 1 through 9 exactly once in each row, column, and 3×3 block. A shared cell has the same entry in all subgrid references.

Rules

• Each active cell contains exactly one number from 1 to 9.
• Each contained 9×9 sudoku satisfies the normal row, column, and 3×3 block rules independently.
• Overlapping cells belong simultaneously to all subgrids they meet.
• Given numbers are not changed.
• Areas without grid cells are not part of the puzzle and are not filled in.
• The puzzle is only solved when each subgrid is complete and free of conflicts.

Orientation in the Diagram

For the examples, we count the rows of the entire diagram from top to bottom and the columns from left to right. Row 4, Column 7 refers to the cell at the intersection of these two axes.

These overall coordinates do not yet specify which sudoku units are relevant. You must always check which 9×9 subgrid the cell belongs to. An overlapping cell can thus have multiple relevant rows, columns, and blocks.

Basic idea for solving

Start with known sudoku techniques: complete houses, individual cell candidates, and hidden single candidates. After each definite entry in a shared cell, switch to the adjacent subgrid and immediately update the candidates there.

If progress stalls, overlaps are not obstacles but additional information. A candidate is only allowed if it fits all affected rows, columns, and 3×3 blocks.

1. Recognize subgrids and their overlaps

Begin not with individual numbers but with the shape. The blue border shows the top subgrid. The yellow area is also used with the middle subgrid.

The shared area lies within overall rows 4 to 9 and overall columns 4 to 12. Each of its 54 cells has only one value but belongs to both subgrid units.

The thick lines help in recognizing the 3×3 blocks. Still, for rows and columns, always count the full 9×9 subgrid, not the entire visible width or height.

2. Close a nearly complete unit

In the displayed intermediate state, consider row 10 of the left subgrid. Only row 10, column 3 is open there.

The eight visible entries contain all numbers from 1 to 9 except 2. Therefore, 2 must be in row 10, column 3. The other subgrids are not needed for this first step.

Such complete houses are the fastest starting point. Check them in each subgrid separately, as a long visible line can belong to multiple different sudoku rows.

3. Find a single cell candidate

Now consider row 2, column 6. The cell is not just the last gap in a single unit; its row, column, and block neighbors must be checked together.

The numbers 1, 2, 3, 4, 5, 6, 7, and 9 are already visible in at least one associated unit. They are thus eliminated. Only candidate 8 remains, which can be confidently entered.

Blue cells show matching exclusion clues. In your solving, you do not need to mark them: The crucial part is to eliminate candidates from all units of the cell.

4. Use a hidden single candidate

Next, we check the 3×3 block of the top subgrid in overall rows 1 to 3 and columns 4 to 6 for the number 7. Several cells in this unit are still empty.

The 7 appears in the displayed notes only in row 1, column 6. The cell also has 8 as a candidate, but within the considered unit, 7 has no other possible place.

Thus, 7 belongs in row 1, column 6. The other open cells here have notes: row 2, column 6: 8; row 3, column 5: 2 and 3; row 3, column 6: 2.

5. Cut candidates in the overlapping cell

Row 9, column 10 belongs to multiple subgrids. Therefore, its candidates cannot be taken from just one direction.

Individual tests give candidates 1, 2, and 4 for the top subgrid; candidates 2 and 4 for the middle subgrid. Only the common intersection 2 and 4 fulfills all involved row, column, and block conditions simultaneously.

This smaller candidate list is already a real progress, even if no value is set yet. Always update shared cells whenever something changes in any of the involved subgrids.

6. Solve a shared cell confidently

Next is the typical multi-sudoku step. Row 9, column 9 lies in the top, left, middle, right, and bottom subgrids.

Consider the column in overall column 9 of the left subgrid; only 8 is missing there. So, 8 is entered there. The conclusion is found in one subgrid. Because it is the same shared cell, the entry applies to all involved grids at once.

After such an entry, do not just check the unit where you found it. Its biggest effect is often on the other side of the overlap.

7. Track the effect into the neighboring grid

8 is now visible in row 9, column 9. Next, consider row 1, column 9. This cell shares an area with the new entry in an adjacent subgrid.

Before the entry, both 4 and 8 were possible there. The 8 is now excluded. Only 4 remains, so row 1, column 9 is also solved.

This logical sequence makes multi-sudoku puzzles much easier: a safe step first, then an immediate control check in the connected grid. This creates a chain without guessing.

8. From a block to a row or column

We consider the top right 3×3 block in overall rows 7 to 9 and columns 7 to 9. There, 1 can only be in row 8, column 8 or row 9, column 8.

All options lie in the same overall column 8. Therefore, 1 must appear within this block on this line.

Outside the block, 1 can be eliminated from the same subgrid line—here, row 1, column 8. The red marks show these exclusions.

9. Evaluate a naked pair

In the top left 3×3 block, in overall rows 1 to 3 and columns 10 to 12, rows 1 and 3, columns 10 and 11, each have exactly the same two candidates: 1 and 9.

These two numbers must split the two blue cells below. Therefore, 1 and 9 cannot appear in any other cells of that unit.

Notes in row 1, column 11 are removed. A pair does not yet assign a number but can prepare new single candidates in the same unit.

Typical solving process

1. Mentally mark the boundaries of all 9×9 subgrids.
2. Search for nearly complete rows, columns, and blocks in each subgrid.
3. Note candidates whenever a cell is not directly decided.
4. Check shared cells from the perspective of all involved subgrids.
5. Immediately follow each new overlap entry into neighboring grids.
6. Then use hidden singles, block-line interactions, and pairs.
7. Repeat until all subgrids are complete.

Common mistakes

• Treat the entire visible line as one sudoku row. Always valid are the nine cells of a specific subgrid.
• Check a shared cell only in the subgrid where it was found.
• Erroneously consider areas outside the drawn figure as cells to fill.
• Force a subgrid in isolation; some puzzles only become clear through overlap information.
• Work on an overlap after a definite entry without updating candidates in the connected subgrid.
• Guess when uncertain, even though switching to another subgrid can give new clues.

Tips for beginners

• Use color-coded border markings for subgrids if the shape initially looks confusing.
• Start where many clues are present, then follow the shared cells.
• Only jot down candidates allowed in all units of the cell.
• Check row, column, and block after each entry, then check overlaps.
• If stuck, switch consciously to another subgrid instead of guessing.

Conclusion

Flower Sudoku does not require new rules. The real challenge is to apply the familiar Sudoku logic cleanly to multiple overlapping 9×9 grids. By consciously tracking borders and shared cells, you turn the large figure into a series of smaller, verifiable steps.