Number Logic Puzzles Rules
Sudoku
No Blocks (Latin Square)
![]() | Latin Square is an n x n array filled with n different digits, each occurring exactly once in each row and exactly once in each column. Latin Squares Rule:
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Rectangular Blocks
![]() | The most common limit is the Rectangular Blocks. A 9x9 grid has 9 blocks, as seen in the picture. Rectangular Blocks Rules:
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Irregular Blocks (Jigsaws)
![]() | Jigsaw puzzle is played the same as Sudoku, except that the grid has Irregular Blocks, also known as cages. Irregular Blocks Rules:
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Diagonal Variants
![]() | It is common to add limits on the placement of the digits, beyond the usual row and column. One of the limits is the Diagonal Variant. Diagonal Variants Rule:
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Combined Variants
![]() | Variants can be combined. For example: the grid can have both Rectangular Blocks and Diagonal Lines. There can also be more than 2 diagonal lines. Rectangular Blocks and Diagonal Variants Rules:
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Overlapping Variants
Overlapping variant consits of several puzzles. Shared blocks are highlighted by a different color. Here are some examples of overlapping Sudokus:
![](/images/sudhelp/ol1_double_doku.png)
![](/images/sudhelp/ol2_sensei.png)
![](/images/sudhelp/ol3_gattai_near2.png)
![](/images/sudhelp/ol4_wing3.png)
![](/images/sudhelp/ol5_gattai3.png)
![](/images/sudhelp/ol6_sohei.png)
![](/images/sudhelp/ol7_butterfly.png)
![](/images/sudhelp/ol8_flower.png)
![](/images/sudhelp/ol9_samurai.png)
![](/images/sudhelp/ol10_gattai8.png)
Killer
![]() | The grid of the Killer Sudoku is covered by cages (groups of cells), marked with dotted outlines. Each cage encloses 2 or more cells. The top-left cell is labeled with a cage sum, which is the sum of all solution digits for the cells inside the cage. Killer Sudoku Rules:
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Greater/Less Than
![]() | Greater Than (or Less Than) Sudoku has no given clues (digits). Instead, there are "Greater Than" (>) or "Less Than" (<) signs between adjacent cells, which signify that the digit in one cell should be greater than or less than another. Greater Than / Less Than Rules:
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Kakuro
![]() | Kakuro is played on a grid of filled and barred cells, "black" and "white" respectively. The grid is divided into "entries" (lines of white cells) by the black cells. The black cells contain a slash from upper-left to lower-right and a number in one or both halves. These numbers are called "clues". Kakuro Rule:
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Kalkuldoku
![]() | The grid is divided into heavily outlined cages (groups of cells). The numbers in the cells of each cage must produce a certain "target" number when combined using a specified mathematical operation (either addition, subtraction, multiplication or division). Kalkuldoku Rules:
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Futoshiki
![]() | Futoshiki is played on a grid that may show some digits at the start. Additionally, there are "Greater Than" (>) or "Less Than" (<) signs between adjacent cells, which signify that the digit in one cell should be greater than or less than another. Futoshiki Rules:
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Straights
![]() | Straights is played on a grid that is partially divided by black cells into compartments. Compartments must contain a straight - a set of consecutive numbers - but in any order (for example: 2-1-3-4). There can also be white clues in black cells. Straights Rules:
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Skyscraper
![]() | The Skyscraper puzzle has numbers along the edge of the grid. Those numbers indicate the number of buildings which you would see from that direction if there was a series of skyscrapers with heights equal the entries in that row or column. For example: if the line has 4 cells and if the first number in the cell is 4, you will see only one skyscraper because the 4-floor skyscraper hides the 1-floor, 2-floor, and 3-floor skyscrapers. Skyscrapers Rules:
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Skyscrapers with Parks
![]() | The Skyscrapers puzzle can have Parks (empty cells). Skyscrapers with Parks Rules:
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Sum Skyscrapers
![]() | The numbers along the edge of the Sum Skyscraper grid indicate the sum of heights of the visible buildings. Sum Skyscrapers Rules:
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Binary
![]() | Complete the grid with zeros (0's) and ones (1's) until there are just as many zeros and ones in every row and every column. Binary Rules:
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Bricks
![]() | Bricks is another type of Latin Square. Grid is divided into pairs and look like brick wall. Bricks rules
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