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Theme: Logical

Author/Opus: This is the 1st puzzle from guest contributor Dan Adams.

Rules: Place digits into some cells and shade all remaining cells so that: each dodecagon contains the digits 1-9 exactly once; digits in cells sharing a vertex with a black triangle add up to the indicated clue number without repeats; and shaded cells cannot share an edge with another shaded cell.

Answer String: Enter the digits in the marked central rows (triangle, hexagon, triangle, …). Use a capital X for shaded cells. Separate each row with a comma. The example has the key “8178XX,243”.

Time Standards (highlight to view): Grandmaster = 16:00, Master = 32:00, Expert = 1:04:00

Solution: PDF

Note: Follow this link for other less common Number Placement puzzles.

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or solve online (using our beta test of Penpa-Edit tools; use tab to shift between a number entry mode and the linex mode where left click+drag draws lines and right click marks X’s)

Theme: 1 to 9 (for patron Veep, who co-wrote this style for the 2016 MIT Mystery Hunt)

Author/Opus: This is the 130th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Fill each cell with a digit from 1 to 9 (1 to 6 in example) so that no digit repeats in any row or column, and also draw a single, non-intersecting loop through some of the cells in the grid. The loop cannot pass through gray cells. Numbers on the outside of the grid show the sum of digits of ALL horizontal/vertical loop segments in that row/column in order. (Note: as in column 5 of the example, only segments that pass horizontally/vertically in a row/column appear as clues; the 5 in that column is not part of a vertical segment and is not represented by a clue). Not all outside clues are given, and unclued rows/columns can have any possible distribution of loop segments/sums.

Answer String: Enter the digits in the 1st row from left to right, followed by a comma, followed by the 6th row from left to right.

Time Standards (highlight to view): Grandmaster = 9:15, Master = 14:00, Expert = 28:00

Solution: PDF; a solution video is available here.

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)

Theme: Prime Numbers

Author/Opus: This is the 125th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Place a digit from 1-4 (1-3 in the example) into some cells so that each digit appears exactly once in each row and column. Numbers outside the grid indicate the sum of all numbers appearing in the corresponding rows and columns. (Digits in adjacent cells are combined to form multi-digit numbers.)

Answer String: Enter the 5th row from left to right, followed by a comma, followed by the 6th column from top to bottom. Use a capital X for empty cells.

Time Standards (highlight to view): Grandmaster = 3:00, Master = 4:00, Expert = 8:00

Solution: PDF

Note: Follow this link for other less common Number Placement puzzles.

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or solve online (using our beta test of Penpa-Edit tools)

Theme: Unique Digits

Author/Opus: This is the 250th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Add digits to some cells so each cell contains a one- or two-digit number. The sum of the numbers in each row and in each column must be 100.

Answer String: Enter all numbers including the new and given digits from left to right, starting with the top row, then the middle row, and then the bottom row. Separate each row with a comma. (For example “123454,362737,52399”.)

Time Standards (highlight to view): Grandmaster = 1:30, Master = 3:00, Expert = 6:00

Solution: PDF

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a letter entry mode and a shading mode. CAPS LOCK is recommended for letter entry.)

Theme: Clue Symmetry and Logic (originally on 2016 Polish Puzzle Championship)

Author/Opus: This is the 120th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Fill some empty cells with the letters A-F (A-D in the example) so that each row and column contains each letter exactly once. The letters outside the grid indicate the first letter seen from that direction, but each row and column has one transparent letter that is ignored by the clues. The transparent letters must be different in each row and column.

See also this example:

Answer String: Enter the letters (including the transparent letter) in the marked rows in order from left to right, separating each row’s entry with a comma. USE CAPITAL LETTERS.

Time Standards (highlight to view): Grandmaster = 2:45, Master = 5:00, Expert = 10:00

Solution: PDF

Note: Follow this link for other less common number placement variations.

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or solve online (using our beta test of Penpa-Edit tools)

Theme: Clue Symmetry and Logic

Author/Opus: This is the 106th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Fill the grid with digits from the indicated range (1 to n) so that no digit is repeated within a row or column. Number clues in the grid indicate the difference between the largest and smallest digits in the visible cells (i.e., going from the clue until hitting an edge or another triangled cell). If there is only one visible cell, the clue number indicates the digit itself.

Answer String: Enter the digits in the 5th row from left to right, followed by a comma, followed by the 7th row from left to right. Ignore the triangled cells.

Time Standards (highlight to view): Grandmaster = 4:15, Master = 9:15, Expert = 18:30

Solution: PDF; a solution video is available here.

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Clue Symmetry and Logic

Author/Opus: This is the 105th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Fill the grid with digits from the indicated range (1 to n) so that no digit is repeated within a row or column. Number clues in the grid indicate the difference between the largest and smallest digits in the visible cells (i.e., going from the clue until hitting an edge or another triangled cell). If there is only one visible cell, the clue number indicates the digit itself.

Answer String: Enter the digits in the 4th row from left to right, followed by a comma, followed by the 10th column from top to bottom. Ignore the triangled cells.

Time Standards (highlight to view): Grandmaster = 4:00, Master = 5:45, Expert = 11:30

Solution: PDF

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Clue Symmetry and Logic

Author/Opus: This is the 104th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Fill the grid with digits from the indicated range (1 to n) so that no digit is repeated within a row or column. Number clues in the grid indicate the difference between the largest and smallest digits in the visible cells (i.e., going from the clue until hitting an edge or another triangled cell). If there is only one visible cell, the clue number indicates the digit itself.

Answer String: Enter the digits in the 7th row from left to right, followed by a comma, followed by the 4th column from top to bottom. Ignore the triangled cells.

Time Standards (highlight to view): Grandmaster = 1:30, Master = 2:00, Expert = 4:00

Solution: PDF

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Clue Symmetry and Logic

Author/Opus: This is the 103rd puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Fill the grid with digits from the indicated range (1 to n) so that no digit is repeated within a row or column. Number clues in the grid indicate the difference between the largest and smallest digits in the visible cells (i.e., going from the clue until hitting an edge or another triangled cell). If there is only one visible cell, the clue number indicates the digit itself.

Answer String: Enter the digits in the 5th row from left to right, followed by a comma, followed by the 4th column from top to bottom. Ignore the triangled cells.

Time Standards (highlight to view): Grandmaster = 1:30, Master = 2:00, Expert = 4:00

Solution: PDF

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Clue Symmetry and Logic

Author/Opus: This is the 102nd puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Fill the grid with digits from the indicated range (1 to n) so that no digit is repeated within a row or column. Number clues in the grid indicate the difference between the largest and smallest digits in the visible cells (i.e., going from the clue until hitting an edge or another triangled cell). If there is only one visible cell, the clue number indicates the digit itself.

Answer String: Enter the digits in the 7th row from left to right, followed by a comma, followed by the 5th column from top to bottom. Ignore the triangled cells.

Time Standards (highlight to view): Grandmaster = 1:15, Master = 2:00, Expert = 4:00

Solution: PDF

Note: Follow this link for other less common Number Placement puzzles.