Nikoli Puzzles

Rules and Tips for standard puzzle types, and their variants
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Mephisto
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Nikoli Puzzles

Post by Mephisto » Sun 27 Feb, 2011 7:35 pm

If you are interested in the rules of 60+ Nikoli puzzle types you should check these links:

http://www.janko.at/Raetsel/Nikoli/index-3.htm (with images)
http://www.janko.at/Raetsel/Nikoli/index-2.htm (without images)

The rules are in English and in German; background information is in German only.

PuzzleScot
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Re: Nikoli Puzzles

Post by PuzzleScot » Sun 27 Feb, 2011 7:53 pm

That's a pretty good reference! Thanks.

detuned
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Re: Nikoli Puzzles

Post by detuned » Mon 02 May, 2011 8:06 pm

Further to this, I have had reason to write out the rules to 16 nikoli puzzles. Any feedback on what I've done would be hugely appreciated!
Akari
Place some light bulbs in the grid. Each numbered black cell indicates how many lights bulbs are adjacent to that cell. The light bulbs emit rays that travel horizontally and vertically until they hit a black cell or the edge of the grid. Each white cell should be illuminated by a light bulb, and no two light bulbs should illuminate each other.
Fillomino
Place a number in each cell of the grid, so that each number is contained in a polyomino of that size. Polyominoes of the same size must not be adjacent via a common cell-edge.
Hashi
Connect each of the numbered islands in the grid via horizontal and vertical bridges. Each island has that many bridges leading away from it, and at most two bridges are allowed to connect a pair of islands. There must be a sequence of bridges that links one given island to any other.
Heyawake
Shade some cells in the grid. The grid is divided up into rooms. If a room is marked by a number, then there must be that many shaded cells within it. Shaded cells should not share an edge, and the remaining unshaded cells should form a connected area via horizontal or vertical paths. The unshaded cells should not traverse more than two rooms in a straight line.
Hitori
Shade in some cells in the grid so that in the remaining unshaded cells at most one of each number appears in any row or column. Shaded cells should not share an edge, and the remaining unshaded cells should form a connected area via horizontal or vertical paths.
Kakuro
Place a digit from 1-9 in each white cell in the grid so that the sum of each horizontal/vertical group of cells equals the number given on its left/top. Digits must not repeat within any sum.
LITS
Place exactly one of the four tetrominos (L, I, T and S) in each marked region of the grid by shading in some squares. Tetrominoes of the same type, up to both rotations and reflections, must not be adjacent via a common cell-edge. The resulting shaded cells in the grid should form a connected area via horizontal or vertical paths, and there should be no 2x2 area of cells completely shaded.
Masyu
Draw a single closed loop in the grid, travelling horizontally and vertically through the centres of each empty cell it passes through. The loop must not intersect/overlap itself. The loop should also pass through each circle in the grid. At a white circle, the loop should travel straight through and make a 90° turn in the cell immediately before or after. At a black circle, the loop should make a 90° turn and extend in the relevant two directions for at least two cells.
Numberlink
Connect matching pairs of numbers in the grid with a line which travels horizontally and vertically via the centres of each cell it passes through. Any given line must not intersect/overlap itself, or any other line.
Nurikabe
Shade some cells in the grid, such that the shaded cells form a connected area via horizontal and vertical paths, and so that there are no 2x2 area of cells completely shaded. The remaining unshaded cells should form several connected islands. Each island should contain exactly one given number in the grid, and this number represents the number of cells of its corresponding island.
Ripple Effect
Place a number in each cell in the grid. The grid is divided up into several regions, and each region should contain the numbers 1-n exactly once, where n is the number of cells in a given region. Any given number m in the grid should be at least m cells away in a horizontal or vertical direction from any other instance of m in the grid.
Shikaku
Divide the grid into rectangles so that each rectangle contains exactly one number. Each number represents the number of cells of its corresponding rectangle.
Slitherlink
Draw a single closed loop in the grid, travelling horizontally and vertically between the lattice points. The loop must not intersect/overlap itself. Numbers in some cells of the grid indicate how many edges of that cell are contained in the loop.
Sudoku
Place a number from 1-9 in each empty cell in the grid such that each row, column and marked 3x3 box contains each number exactly once.
Suraromu
Draw a single closed loop in the grid, travelling horizontally and vertically though the centres of the cells it passes through. The loop must not intersect/overlap itself. The loop begins (and ends) at the circled number, and travels perpendicularly through each of the dotted gates exactly once. The gates are labelled in the order that the loop passes through. The circled number indicates the total number of gates.
Yajilin
Draw a single closed loop in the grid, travelling horizontally and vertically through the centres of each empty cell it passes through. The loop must not intersect/overlap itself.

Any empty cell the loop does not pass through must be shaded in. Shaded cells must not share an edge. Some cells have numbered clues; these indicate how many cells in the given direction are to be shaded.
Thanks for taking a look - any comments/criticisms are more than welcome!

Mephisto
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Re: Nikoli Puzzles

Post by Mephisto » Tue 03 May, 2011 5:27 am

Akari
should -> must (also in all other descriptions, see http://www.faqs.org/rfcs/rfc2119.html :o)
are adjacent to that cell -> are orthogionally adjacent to that cell

Heyawake
more than two rooms in a straight line -> more than two rooms in a horizontal or vertical straight line

Nurikabe
"conected islands"? Not the islands are connected, but the cells must be connected.

Suraromu
"The gates are numbered" -> "Some gates are numbered" (all unnumbered gates may be passed in any order)

detuned
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Re: Nikoli Puzzles

Post by detuned » Tue 03 May, 2011 11:44 am

Thanks a lot, very helpful - especially that link. It is nice to get things right!

Ours brun
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Re: Nikoli Puzzles

Post by Ours brun » Thu 12 May, 2011 5:32 pm

Masyu

I would replace
At a white circle, the loop should travel straight through and make a 90° turn in the cell immediately before or after.
by
At a white circle, the loop should travel straight through and make a 90° turn in the cell immediately before or after, or both.
Otherwise, if I am right, one can interpret "in the cell immediately before or after" as "in exactly one of these two cells".

(also, like Mephisto said, should should become must)

Thanks to you two, it is especially useful for non-english people; I sometimes have trouble to express some rules in english with all due clarity.
http://enigm-attic.blogspot.com --> sudoku variants and other handcrafted logic puzzles.

Mephisto
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Joined: Tue 18 Jan, 2011 12:28 pm

Re: Nikoli Puzzles

Post by Mephisto » Thu 12 May, 2011 8:03 pm

Masyu:

I think the "or both" is an improvement.

In Latin, there are two different "or"s: "vel" is the inclusive "or" (detuned used) and "aut" is the exclusive "either-or". Unfortunately, there is no such distinction in most ouf our modern languages. We have a simple inclusive "or" and must express the exclusivity by "either". What makes things difficult is that in colloquial language the simple "or" is often used as "either-or".

Mephisto

Mephisto
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Re: Nikoli Puzzles

Post by Mephisto » Fri 13 May, 2011 10:52 am

I just added 16 new puzzle descritions to the Nikoli pages (rules in English and German, background information in German only, all with examples):

Bodaburokku (ボーダーブロック), Bonsan ( ぼんさん) and Heyabon (へやぼん), Firumatto (フィルマット), Hakoiri (はこいり), Kojun (コージュン), Kuroshuto (クロシュート), Mejirinku (メジリンク), Nanro (ナンロー), Paipurinku (パイプリンク), Renban Madoguchi (連番窓口), Roma (ろーま), Shugaku (修学旅行の夜), Tatamibari (タタミバリ), Usotatami (ウソタタミ), Viu (ヴィウ)

Currently there are 78 puzzle descriptions online:

http://www.janko.at/Raetsel/Nikoli/index-3.htm (with images)
http://www.janko.at/Raetsel/Nikoli/index-2.htm (without images)

Mephisto

SnideAsides
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Re: Nikoli Puzzles

Post by SnideAsides » Tue 19 Jul, 2011 1:42 am

What's the difference between Mochikoro and Mochinyoro? Right now, they both have the same rules.

Mephisto
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Re: Nikoli Puzzles

Post by Mephisto » Tue 19 Jul, 2011 6:43 am

The rules are almost the same, but the last sentence in the Mochinyoro rules reads: "The black cell must not cover an area of 2x2 or larger and must not be rectangular (or square)." (the bold half-sentence is missing in Mochikoro). Note that this is different from the 2x2-rule; it also excludes black areas of e.g. 1x1 or 2x1 or 3x1.

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