## SudoCue - HaniDoku Introduction |

This site offers a daily HaniDoku with an archive of previous puzzles and solutions. Check our freeware HaniCue program. You can play HaniDoku on your Windows PC with this unique program. ## What is HaniDoku?
A Hanidoku puzzle looks like a honeycomb. It has hexagonal cells.
Like in regular Sudoku, there are 9 rows, but there are no columns.
Instead, there are lines that run in 60 degree angles from the horizontal rows.
We call the ascending lines
To identify cells in the grid, I advice you to use The lines have different lengths. Each line type comes in sizes 5-6-7-8-9-8-7-6-5. There is only one line for each type that has size 9, all shorter sizes appear twice. The lines of length 9 must contain all digits 1 through 9. This rule is similar to the rule of Sudoku. However, the shorter lines must contain consecutive numbers. For example, =4= contains 8 cells. It can either contain digits 1 through 8 or digits 2 through 9. One of the new aspects of HaniDoku is that you do not know which of these two series is used. In your solving strategies, you must make a distinction between mandatory digits (2-8) and optional digits (1,9). A line of size 5 has many alternative series: 12345, 23456, 34567, 45678 or 56789. The only mandatory digit in such a line is 5.
The name ## HaniDoku SpecificationsThe most interesting part of this format are the lines in 3 directions, with different sizes. Here is a table that shows the possible digit series for each line size:
An optional digit can become mandatory in an individual puzzle, when more information becomes available when you solve it. There are different reasons that make an optional digit mandatory: - The digit is given as part of the puzzle. It is already placed in a cell.
- The digit is a naked or hidden single in one of the cells on the line. It must be placed in that cell.
- The digit falls in the gap between two placed or mandatory digits.
- There are no candidates left for the alternative. When no candidates for digit 1 are left on a line of size 5, digit 6 automatically becomes mandatory.
- The digit is part of a disjoint subset. This is a familiar sudoku technique that can also be used in HaniDoku.
Optional digits can also be eliminated from a line. On a line of size 5, 6 or 7, you can find optional digits that require another optional digit to be present. For example, digit 9 requires digit 8 to be available, otherwise it cannot be used in a series. When digit 8 has no candidates left in a line, digit 9 can also be eliminated from the entire line. You can save or print the worksheet page, to create worksheets that enable you to solve HaniDoku manually. |

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