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Sudoku Resources are Everywhere...
Sudoku Forums
English
-
Sudoku Xtra forum
- Fairly busy forum with discussion of all aspects of Sudoku
and related puzzles, as well as the monthly Sudoku Xtra
magazine.
-
YouPlay! Forums
- Engage with a community of dedicated Sudoku enthusiasts via
specialty forums and site-wide chat. You can even get in touch
with the Sudoku generator and site developers.
-
Sudoku Players' Forums
- Originally the most active Sudoku forum, started by Wayne
Gould, but currently owned by RealNetworks, Inc. Many
new solving techniques were developed by its members but were
lost in a server failure - see the following entry.
-
New Sudoku Players' Forum
- Created from a 2009 backup of the original Players’ Forums
by concerned members when it crashed in 2010. Over 70,000
postings were recovered including those covering the development
of many major techniques. The forum is still live.
-
Sudoku Programmers
- A forum where programmers exchange ideas about writing
Sudoku computer programs. Not as active as it used to be, but
still a considerable resource for finding solving techniques.
This forum is also used by Angus Johnson as a support
forum for his
Simple Sudoku program.
-
Sudoku Discussions
- This forum was founded by the late Mike Mepham. It is
currently managed by Andrew Stuart, who supplies the
Sudokus for the Daily Telegraph in the UK and the LA
Times. The Eureka board has very lively discussions
that explore the uncharted territories of the Sudoku world.
-
SudoCue Users
- A forum hosted by Ruud, the author of
SudoCue and
SumoCue. An excellent place to learn how to solve extremely
difficult Sudokus and several
Sudoku Variations. It has a very active
Killer Sudoku community.
-
Daily Sudoku
- A forum for the Daily Sudoku website, hosted by Sam
Griffiths-Jones.
-
DJApe - The Home of Perfect Sudoku
- A forum hosted by DJ-Ape, the author of
Perfect Sudoku. A perfect place to discuss the
Killer Sudoku variant.
-
Sudoku Assistenten Forum
- A forum hosted by Havard, one of the authors of the
Sudoku Assistenten program. Includes threads for support,
sharing sudokus and advanced techniques.
-
Sudoku Puzzles - Sudoku Tips
- Frequent tips and illustrated puzzle proofs by Steve K,
as well as discussion between the various members.
-
SudokuSolver Forum
- Hosted by R.C. Broughton, author of the
SudokuSolver program. A forum for Sudoku enthusiasts to
share puzzles, techniques and software.
Dutch
-
SudokuPlaats forum
- A small but clean forum to discuss Sudoku and off-subject
matter in Dutch.
-
Players & Programmers forum
- The administrator has left the building. Spammers have taken
over the forum.
Vietnamese
-
sudoku.vn
Online Daily Sudoku Puzzles
Ordinary Sudoku
-
BrainBashers Sudoku
- Daily
sudokus with six levels of difficulty. The list of
solving techniques needed for their puzzles are listed
here. Solutions to each puzzle includes a
walkthrough. The archive dates back to 2005 January 1.
-
Sudoku XL
- Millions of sudoku to be played online or printed. High
score function and the possibility to print several sudoku per
printed page. Levels that suits both beginners and more advanced
sudoku solvers.
-
Daily Sudoku Puzzles
- A free online sudoku with built in solver.
-
Sudoku Tips
- Tips and strategies to solving sudoku.
-
Free Sudoku
- Contains a free sudoku game download, daily sudoku and
printable sudoku puzzles.
-
Sudoku Center Online
- 9 sudoku puzzles of 5 different levels. You can find Sudoku
Solver too.
-
YouPlay!
- Free puzzle website created by Lovatts Publications, leaders
in the field of puzzle production. This site has Sudoku to suit
all playing levels, a site-wide chat room and a growing
community of Sudoku enthusiasts.
-
Fed-sudoku
- 3 clasic sudoku puzzles and one nonconsecutive sudoku puzzle
daily and many sudoku variants, everything online and with many
scoreboards and statistics. (Slovak and English versions)
-
Sudoku.com.au
- 9 sudoku puzzles daily, all free. A great online player, but
the biggest drawcard is the huge active community which is very
friendly. They have lots of online helpers, as well as blank
printable sheets and a sudoku blog which gives out daily solving
tips.
-
The Daily Nightmare
- A daily puzzle from the creator of
SudoCue which more than lives upto its name. Not for the
faint hearted - as the full arsenal of
solving techniques is required. The puzzle's archive dates
back to December 2005.
-
One Trick Pony
- A daily puzzle from the creator of
SudoCue which requires a good range of
solving techniques, plus one advanced step to solve. The
puzzle's archive dates back to November 2006.
-
The Daily Lite
- Four new puzzles everyday, from the creator of
SudoCue, of four levels of difficulty. Ideal for developing
and enhancing
solving techniques.
-
Times Online - Sudoku
- The London Times. Two daily puzzles of different
levels of difficulty. The most advanced techniques required to
solve the hardest (Super Fiendish) Times daily puzzles
are
X-Wings,
Naked Subsets and
Hidden Subsets. Upto seven days of archived puzzles. Links
to recent Sunday Times puzzles and published Times
supplement collections.
-
Sudoku.org.uk
- A daily Mike Mepham puzzle of varying levels of
difficulty. The hardest puzzles, the Diabolical and the
weekly Extreme, require a wide range of
solving techniques. A thirty day puzzle archive. The site
also publishes daily
Jigsaws and
Killers.
-
Daily Mail (uk) - Sudoku
- Two daily puzzles of different levels of difficulty. The
most advanced techniques required to solve the hardest
(Diabolical) daily puzzles are
Naked Subsets and
Hidden Subsets. The puzzle archive dates back to 2005
October 8.
-
Guardian Unlimited (uk) - Sudoku
- A daily puzzle of varying levels of difficulty (Mon to Sat).
The most advanced techniques required to solve the hardest
(Hard) daily puzzles are
Naked Subsets and
Hidden Subsets. The puzzle archive dates back to May 2005.
-
The Daily SuDoku
- A daily Sudoku with difficulty varying from easy to
very hard. The archive goes back to January 2005.
3
Sudoku Variations are also published daily.
-
playr.co.uk/sudoku
- Daily
sudokus by Gaby Vanhegan with six levels of difficulty. The
hardest puzzles have at least Nightmare standard. The
archive goes back to 2005 October 10.
-
7star Sudoku
- Mostly daily symmetrical
sudokus which occassionally require the most advanced
techniques. The archive dates back to 2006 May 1.
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Online Picture Sudoku
- Sudoku puzzles with pictures (numbers also available)
playable online and generated at random each time the page is
loaded. All can be solved with more simple techniques, and have
only one solution. You can put Sudoku on your own site with your
own pictures.
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Free Sudoku Games
- Play free sudoku games online or just download the pdf
containing the puzzle and play offline.
-
Kodden's Daily Sudoku
- A new sudoku puzzle every day and randomly generated puzzles
of various difficulty.
-
Sudoku puzzles for beginners
- Free on-line Sudoku game that offers assistance in finding
the correct solution. Solve one of the included puzzles or enter
your own.
-
Sudoku By Zol
- Free unlimited puzzles: 5 difficulty levels. Unique
efficient user interface, especially for Pencil Marks. Enter
your own puzzles and solve them yourself online. All puzzles are
printable puzzles. Become a fan on the
Sudoku By Zol Facebook Page.
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PuzzleMix
- With new puzzles online every day, and thousands of active
solvers, PuzzleMix features Sudoku at a range of sizes and
difficulties for online play, complete with a wide range of
intelligent solving assistants
-
Sudoku Snake
- An extensive website containing explanations of
over 40 solving techniques,
daily printable puzzles at 9 different difficulty levels,
and other sudoku information.
-
Online sudoku game
- Free online sudoku for all players from kids (4x4 board with
flowers) to most experienced (program offers mode with automatic
"pencil marks" and other features that helps to solve difficult
sudoku puzzles). Requires Java.
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Fishy Sudoku
- Not for beginners! New puzzles daily require X-Wing, Y-Wing
and the occasional Swordfish. Great interface, automatic (but
still editable) pencilmarks. Hints engine helps you when you get
stuck. Complete archive available.
Play on facebook.
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Mister Sudoku
- An extensive collection of sudoku puzzles with a wide
variety of types (Standard / Jigsaw / Killer), sizes and
difficulties. Hints engine helps if you're still learning or
simply stuck. Also includes a variety of scoreboards which track
your performance globally, nationally and amongst your Facebook
friends.
Play on facebook.
Online Sudoku Puzzle Collections
Ordinary Sudoku
-
Pure Sudoku - Printable Sudoku Puzzles
- A collection of printable sudoku puzzles at 5 difficultly
levels.
-
New Sudoku Players’ Forum
- Has many different puzzle collections in the
General/puzzle forum. A good place to start is the
Puzzle collections sorted by solving qualities.
-
SudoCue Downloads
- Has 7 download Sudoku files available, for the
SudoCue Program. The puzzles collections are aimed at all
different levels of playing ability. nb Beginners should start
with The Learning Curve Collection.
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Sudoku Assistenten forum - Share sudokus
- A collection of interesting and difficult puzzles posted by
the forum's members.
-
Web Sudoku
- A different puzzle is presented for each log in. It is also
an online puzzle generator, where the level of difficulty (four
levels) is chosen by user. It appears that the most advanced
technique that is required to solve the hardest Web Sudoku
puzzles (Evil) are
Naked Subsets and
Hidden Subsets.
-
Minimum Sudoku
- Contains 36628 distinct starting grids with 17
givens. (Currently, it is believed that at least 17 givens
are needed to construct a
valid puzzle.)
-
Sudoku puzzles
- Puzzles are divided into eight difficulty levels.
-
Color coded sudoku puzzles
- Free online color coded sudoku puzzle solver with timer,
pencil, graph, hints, multiple difficulty level etc
-
Razzle
- Free online/printable sudoku puzzles ranging from easy to
expert. Expert level requires X-Wing, XY-Wing, Simple Colouring,
and Swordfish techniques to solve.
Terminology
From Sudopedia (Note: the
links in this section are disabled)
The Sudoku community has developed its own
terminology. Most of the basic terms are now widely accepted, but
some concepts are known by many different names. Here is an
alphabetic list of the most commonly used terms.
0-9
-
3D Medusa
- A
coloring technique for multiple digits.
-
45 rule
- A rule stating that the sum of the
cells in a
house must be 45. This is most applicable to
Killer Sudoku.
A
-
Advanced Coloring
- An alias used for
3D Medusa.
-
AIC
- An acronym used for
Alternating Inference Chain.
-
Aligned Pair Exclusion
- A solving technique that examines the
possible configurations for a pair of cells in an intersection.
-
Aligned Triple Exclusion
- A solving technique that examines the
possible configurations for a triple of cells in an
intersection.
-
Almost Locked Set
- A set of N cells with candidates
for N+1
digits.
-
ALS
- An acronym used for
Almost Locked Set.
- Alternating Inference
- See:
Inference
-
Alternating Inference Chain
- A
chain with alternating strong and weak
inference.
-
APE
- An acronym used for
Aligned Pair Exclusion.
-
Ariadne's Thread
- A metaphore used for
backtracking.
-
Asymmetric Puzzle
- A puzzle is asymmetric if its
particular geometric shape is such that rotations or reflections
do not result in the same bit pattern of clues. Essentially all
of the different digits in the clue are converted into a single
bit which is on if the clue for that position was given and off
if there is no clue for that position.
-
ATE
- An acronym used for
Aligned Triple Exclusion.
-
Automorphic solution grids
- ??
B
-
B/B Plot
- A diagram showing
strong links.
-
Backdoor
- Placement of a digit from the solution
into a cell which reduces the difficulty level of the remaining
puzzle.
-
Backtracking
- Return to an earlier position in the
solving path, after a contradiction or a dead end has been
reached.
-
Band
- An alias used for
floor.
-
Bifurcation
- A limited form of
Trial & Error where only constraints with 2 remaining
candidates are considered.
- Big Number
- Collective term for
given and placed digits, as opposed to little number
for
pencilmarks.
-
Bilocal Unit
- A unit constraint with only 2
candidates left.
-
Bivalue Cell
- A cell with only 2 candidates left.
-
Bivalue Universal Grave
- A pattern in which all cells have 2
candidates, which causes the Sudoku to have 0 or 2 solutions.
-
Block
- An alias used for
box.
- Block-Block Interaction
- An alias used for
Locked Candidates type 2.
-
Bowman Bingo
- A solving technique that does a
systematic analysis of all implications for a move.
-
Box
- A group of 9 cells in a 3x3 formation.
In a Sudoku grid, boxes usually have a thicker border.
- Box Exclusion
- A method by which hidden singles can be
found by excluding candidates within a box using non-duplication
with rows and columns; an alias for
cross-hatching
-
Box-Line Reduction
- An alias used for
Locked Candidates type 2.
-
Boxcol
- The intersection of a box and a column.
-
Boxrow
- The intersection of a box and a row.
-
Braid Analysis |
Braiding
- A solving technique that analyzes the
way digits are organized in a
chute.
-
Bridge
- A weak link that connects 2 clusters in
a
coloring technique.
-
Broken Wing +
Guardians
- A solving technique that uses
Turbot Fish patterns and Guardians to make eliminations.
-
Buddy
- An alias used for
peer.
-
BUG
- An acronym used for
Bivalue Universal Grave.
-
BUG Lite
- A
deadly pattern that is between
Unique Rectangle and
BUG.
C
-
Cage
- Isolated part of the grid in a
Killer Sudoku, with the sum of all caged cells in the top
left corner.
-
Candidate
- A possible digit that may be placed
into a cell. Candidates are represented by
pencilmarks.
-
Candidate elimination cell
- A cell that contains a candidate
capable of causing a contradiction in a
fish
pattern.
-
Canonical Form
- A standard form of presentation which
will identify if two puzzles are
scrambled duplicates.
-
Cell
- A small square in a Sudoku grid that
can contain a single digit.
-
Cell Set
- An alias used for
house.
-
Chain
- A series of linked cells or candidates.
-
Chute
- A part of the grid which is either a
floor or a
tower.
-
Claiming
- An alias used for
Locked Candidates type 2.
-
Clue
- An alias used for
given.
-
Cluster
- A group of candidates which are all
interconnected with strong links. Used in
Coloring.
- Column Exclusion
- A method by which hidden singles can be
found by excluding candidates within a column using
non-duplication with rows and boxes; a process similar to
cross-hatching but within a column.
-
Color Trap
- A coloring technique that eliminates
candidates outside a single cluster.
-
Color Wing
- A coloring technique that eliminates
candidates using multiple clusters.
-
Color Wrap
- A coloring technique that eliminates
candidates inside a single cluster, by means of contradiction.
-
Coloring
- A solving technique that uses colors to
identify conjugate pairs. Can be simple (single or one chain) or
multi- (two chains). Also described as Magnetism by some
authors.
-
Column
- A vertical line in the grid, containing
9 cells.
-
Common Peer Elimination
- If all cells in a particular constraint
contains a particular digit as a candidate sees another cell,
then that digit can be eliminated from the latter cell. This is
a basic technique used in
Sudoku Variations with irregular groups of cells.
-
Conflict
- An alias used for
contradiction.
-
Conjugate pair
- The last 2 candidates for a particular
digit in a single house. Used in
Coloring.
-
Connected pair
- A pair of candidates which cannot both
be false at the same time.
-
Constraint
- A restriction derived from the rule.
Sometimes used as an alias for
house.
-
Contradiction
- The state of the grid in which the
puzzle no longer complies with the rule.
-
Cross-Hatching
- A method by which hidden singles can be
found.
-
Crossover
- A basic technique for
Sudoku-X, which looks at eliminating common peers of
diagonal cells.
D
-
Deadly Pattern
- A pattern that would cause a Sudoku to
have multiple solutions.
- See also:
Unavoidable Set
-
Diagonal
- A group of 9 diagonally connected
cells. In
Sudoku-X and other variants, the diagonals must also contain
digits 1 through 9.
-
DIC
- An acronym used for
Double Implication Chain.
-
Digit
- A number between 1 and 9 which can be
placed into a cell.
-
Disjoint Subset
- An alias used for
subset.
-
Division
- A method by which the cells in the grid
are divided into 9 houses. All rows together form a division and
so do all columns and all boxes.
-
Double Implication Chain
- A chain that propagates implications in
both directions.
E
-
Eliminate
- Removing a candidate from the grid.
-
Empty Rectangle
- A solving technique that uses a strong
link and grouped candidates.
-
Equivalence Marks
- A solving technique that uses marks to
represent
parity instead of colors.
- See also:
GEM
|
Graded Equivalence Marks
-
Equivalent
- A term which indicates that a group of
candidates must be true or false together.
-
ER
- The acronym for
Empty Rectangle.
-
Error
- An alias used for
contradiction.
-
Eureka | Eureka notation
- A notation system for chains and loops.
- Exclusion
- The process of removing a candidate
from the grid
F
- Family
- An alias for
peer
- Fillet-O-Fish
- See:
Finned Fish
-
Fin
- The additional candidate(s) in the box
constraint that belongs to a
Finned Fish
-
Finned Fish
- A variety of
fish
that uses an additional box constraint.
-
Fish
- A set of solving techniques that
compares sets of unit constraints for a single digit.
-
Fishy Cycle
- A loop formed by candidates for a singe
digit.
- See also:
Turbot Fish
-
Fixed Digit | Number | Value
- An alias used for
given.
-
Floor
- A part of the grid containing 3 rows
and 3 boxes.
-
Floor Minlex
- A minlex of a floor. There are 416
possible floor minlexes.
-
Forced Digit
- An alias used for
Naked Single.
-
45 rule
- A solving technique in
Killer Sudoku making use of the knowledge that the digits in
each house add to 45.
-
Franken Fish
- A variety of
fish
that uses multiple additional box constraints.
-
Full House
- A house with only a single empty cell.
G
-
Gattai
- A puzzle with 2 or more overlapping
Sudokus.
-
GEM
- An acronym used for
Graded Equivalence Marks
-
Given | Given Digit | Given Number
- A digit placed in a cell by the puzzle
setter. It cannot be changed by the player.
-
Graded Equivalence Marks
- A solving technique that uses marks in
the
pencilmark grid to represent different grades of parity.
- See also:
Equivalence Marks
-
Gerechte Design
- A special design of a Latin square
where the n × n Latin square grid is also divided into n
regions, with n cells in each.
-
Grid
- 81 cells organized in 9 rows and 9
columns.
-
Group
- An alias used for
house.
-
Guardian
- See:
Broken Wing
-
Guess
- A digit placed into a cell without a
logical reason.
H
-
Hatching
- An alias used for
Cross-Hatching.
-
Hidden Single
- A unit constraint with only a single
candidate remaining. The digit can be placed in the candidate's
cell.
-
Hidden Subset -
Hidden Pair |
Hidden Triple |
Hidden Quad
- A solving technique that isolates a
group of cells and digits from the remainder of a house.
-
Hinge
- An alias used for
Empty Rectangle.
-
Hint
- An alias used for
given.
-
House
- A group of 9 cells that must contain
digits 1 through 9. A house can be a row, a column or a box in
standard Sudoku.
I
-
Implication
- Effect on a candidate caused by the
true or false state of another candidate.
- Improper puzzle
- An alias used for
invalid.
-
Inference
- Interaction between the true or false
states of 2 linked candidates.
-
Initial Digit | Number | Value
- An alias used for
given.
-
Innie
- In
Killer Sudoku, a
cell
that does not belong to any of the selected
cages,
but lies inside the tested
house(s).
-
Innie-outie difference
- In
Killer Sudoku, the difference between the
innies and
outies may be used to
eliminate candidates.
-
Intersection
- A part of the grid where 2 houses share
one or more cells. Mostly used for intersections between a box
and a row or column.
-
Intersection Removal
- An alias used for
Locked Candidates.
-
Invalid
- A
Sudoku is invalid if it has no solutions or multiple
solutions.
- Irreducible puzzle
- An alias used for
Minimal Puzzle
-
Isomorphic Puzzles
- Two puzzles (puzzles or solution grids)
are isomorphic if they can be converted into one another through
renumbering or allowed geometrical transformations. There are
6,670,903,752,021,072,936,960 different solution Sudoku grids,
but only 5,472,730,538 of these grids are unique. Thus there are
on average about 1.218 x 10^12 isomorphic Sudoku solutions per
unique solution.
J
-
Jellyfish
- A
fish of size 4.
-
Jigsaw
- A Sudoku variant that has irregularly
shaped regions.
K
-
K9
- A way to reference
Sudoku
cells,
by using a letter for the
row
and a number for the
column.
-
Killer | Killer Sudoku
- A Sudoku variant where givens are
replaced by cages labeled with the sum of the digits to be
placed inside them.
-
Killer Convention
- In
Killer Sudoku, the convention that all digits in each
cage
is distinct.
-
Killer Subset
- An extension of the
Subset technique that is applicable to
Killer puzzles.
-
Kraken Fish
- A
fish pattern with indirect connections to a candidate which
can be eliminated.
L
-
Last Digit
- The last placement of a digit.
- Last Value
- : An alias used for
Last Digit
-
Law of Leftovers
- A solving technique used for
jigsaw Sudokus.
-
Line
- A house that is either a row or a
column.
-
Line-Box Interaction
- An alias used for
Locked Candidates.
-
Link
- Connection between 2 cells or
candidates. See also:
Strong link and
Weak link.
-
Little Number
- An alias used for
pencilmark.
-
Locked Candidates
- A solving technique that uses the
intersections between lines and boxes.
-
Locked Pair
- A
Naked Pair located in a single
intersection.
-
Locked Triple
- A
Naked Triple located in a single
intersection.
-
Locked Set
- An alias used for
subset.
-
LoL
- An acronym used for
Law of Leftovers
-
Loop
- A loop of linked cells or candidates.
M
-
Magic Cell
- An alias used for
backdoor.
-
Mark | Markup
- An alias used for
pencilmark. Also the act of placing them in the grid.
-
Mathematically equivalent
- Puzzles which are essentially the same.
By permutating rows, columns and digits, one can be mapped to
the other.
-
Maximal
- A puzzle is maximal if it has the
maximum number of clues possible, and yet there is a unique
solution. In a game on a NxN grid, then the maximum number of
clues is N^2-3.
-
MC
- An acronym used for
Multi-Colors
-
Mini-col
- An alias used for
boxcol.
-
Minimal
- A puzzle P is minimal if it has one and
only one solution and if every given is necessary. In other
words, if any one of the givens is deleted, then the puzzle
obtained has more than one solution.
-
Mini-row
- An alias used for
boxrow.
-
Minlex-Puzzle
- ?
-
Multi-Colors
- A
coloring technique that uses more than 2 colors, forming
multiple clusters.
-
Mutant Fish
- A
fish pattern with an odd mixture of rows, columns and boxes.
N
-
Naked Single
- A cell with only a single candidate
remaining. It can be placed in the cell.
-
Naked Subset -
Naked Pair |
Naked Triple |
Naked Quad
- A solving technique that isolates a
group of cells and digits from the remainder of a house.
-
Nishio
- A limited form of
Trial & Error where only candidates for a single digit are
considered.
-
Node
- A cell in a chain or loop.
-
Nonet
- An alias used for
box.
This is the preferred term for
Killer Sudoku.
-
Number
- An alias used for
digit.
O
-
Opposite | Opposite Parity
- Different parities in a single cluster.
Only one of them can be true.
- See also:
Conjugate pair
-
Orbit
- A group of cells which must all contain
a given or be empty in order to preserve
symmetry.
-
Outie
- In
Killer Sudoku, a
cell
that belongs to one of the selected
cages,
but lies outside the tested
house(s).
P
-
Parity
- Status of a candidate relative to other
candidates. Parity is represented by a color or parity mark.
-
Pattern Overlay Method
- A solving technique that examines
possible ways to place remaining candidates in the grid.
-
Peer
- A cell that shares a house with another
cell.
-
Pencilmark
- The representation of a candidate.
-
Pincer
- One of the end cells in an
XY-Wing or
XYZ-Wing.
-
Pinned Digit
- An alias used for
Hidden Single.
-
Pivot
- The central cell in an
XY-Wing or
XYZ-Wing.
- Placement
- Placing a candidate into an unsolved
cell, thus changing it to a solved cell.
-
PM
- The acronym for
pencilmark.
-
Pointing Pair
- An alias used for
Locked Candidates.
-
POM
- An acronym used for
Pattern Overlay Method
-
Possibility
- An alias used for
candidate.
-
Proper puzzle
- An alias used for
valid.
- Puzzle
- Any incomplete Sudoku grid which
follows the One rule.
There may be one or more solutions.
R
-
Random Puzzle
- For any given computer program which
creates puzzles, a random puzzle essentially is a puzzle which
is created
chaotically, that is to say so randomly that the created
puzzle would never (for all practical purposes) be created
again.
- Reducible puzzle
- An alias used for a
Proper puzzle
-
Region
- An alias used for
box.
- Remaining Possibilities
- An alias for
candidate
-
Remote Pair
- A solving technique that combines
several
Naked Pairs.
-
Restricted common
- A digit which cannot be present in 2
Almost Locked Sets at the same time.
-
rncn
- A way to reference
Sudoku
cells,
by using a
row
number and a
column number.
-
Rookery
- A term for the pattern of 9 cells that
a one digit could occupy in a completed Sudoku grid. A k-Rookery
would be the pattern of cells that k-digits could occupy.
-
Row
- A horizontal line in the grid,
containing 9 cells.
- Row Exclusion
- A method by which hidden singles can be
found by excluding candidates within a row using non-duplication
with columns and boxes; process similar to
cross-hatching but within a row.
-
Row Minlex
- A row minlex is a particular
canonical form which represents the set of isomorphic
solution grids. It has the first row as the digits 1-9 in
sequence, hence the name (see wiki page for more details).
- Row/Column-Block Interaction
- An alias used for
Locked Candidates type 1.
-
Rule
- The one rule of Sudoku. Complete the
grid in such a way that each row, column and box contain digits
1 through 9.
S
-
Samunamupure
- Alias for
Killer Sudoku. It is the Japanese form of "sum number"
-
Samurai
- An variant with 5 overlapping Sudokus
in an X
pattern.
-
Sashimi Fish
- A variety of
fish
where not all defining candidates are present.
-
SC
- An acronym used for
Simple Colors
-
Scramble
- Create a
mathematically equivalent grid from a given grid.
-
Seafood |
Sealife
- Aliases used for
Fish.
-
See
- Two
cells
see each other if they belong to the same
constraint (row,
column or
box).
-
Sector
- An alias used for
house.
-
Segment
- An alias used for
intersection.
-
Set
- An alias used for
house.
-
Shaolin
- A
Gattai-25
Sudoku variant with 36 overlapping
boxes.
-
Shi Doku
- A NxN Sudoku variant played with a 2x2
box. Thus the grid is 4x4 and the digits 1-4 can be used.
-
Simple Colors
- A
coloring technique that is limited to 2 colors, using a
single cluster.
-
Single
- Elementary solving technique, using the
fact that only a single candidate is left for a constraint.
-
Skinny Fish
- See:
Sashimi Fish
-
Skyscraper
- A particular variety of
Turbot Fish.
-
Solution
- The answer to the puzzle. A grid where
each cell contains a digit between 1 and 9 without violating the
rule.
-
Solving path
- A list of steps that shows how a
particular puzzle is solved.
-
Square
- An alias used for
cell.
-
Squirmbag
- A
fish of size 5.
-
SSTS
- Simple Sudoku Technique Set. The set of
techniques supported by the
Simple Sudoku program.
-
Stack
- An alias used for
tower, sometimes used as an alias for
boxcol.
- Strong Inference
- see:
Inference
-
Strong link
- A link caused by a
bivalue cell or
bilocal unit.
-
Subgrid
- An alias used for
box.
-
Subset
- Usually refers to
Naked Subset or
Hidden Subset.
-
Sudoku
- A puzzle defined by a grid with givens
and a unique solution, which can be found by completing the grid
according to the rule.
-
Sudoku-X
- A
Sudoku variant where every
diagonal must also contain the
digits 1 to 9.
-
Subset
- A set formed by N cells and N
digits, which are or can be isolated from the remaining cells
and digits in a house.
-
Sumo
- A
Gattai-13
Sudoku variant with 16 overlapping
boxes.
-
Swordfish
- A
fish of size 3.
-
Symbol
- An alias used for
digit.
-
Symmetric Puzzle
- A puzzle is symmetric if its particular
geometric shape is such that rotations or reflections result in
the same bit pattern of clues. Essentially all of the different
digits in the clue are converted into a single bit which is on
if the clue for that position was given and off if there is no
clue for that position.
T
-
Tabling
- A form of
Trial & Error where all candidates are tried.
- Target Cell
- A cell selected for analysis of
remaining possibilities.
- Target Number
- A number selected for analysis using
techniques that seek to find the location of the number within a
group.
-
Tower
- A part of the grid that contains 3
columns and 3 boxes.
-
Traveling Pairs
- An alias used for
Braid Analysis.
-
Trebor's Tables
- An alias used for
tabling.
-
Trial & Error
- A solving technique that eliminates
candidates by proving that their placement leads to a
contradiction.
-
Turbot Fish
- A solving technique that uses loops of
odd length for a single digit.
U
-
Unavoidable Set
- A group of cells in the solution grid
that requires at least one given.
-
Unique Rectangle
- An
Unavoidable Set with a rectangular shape.
- See also:
Deadly Pattern
- Unique Solution
- The assumption that a Sudoku has a
single solution. Subject of debate, especially when used in
solving techniques.
-
Uniqueness Test
- A series of solving techniques in which
the solver avoids
Unique Rectangles.
-
Unit
- An alias used for
house.
V
-
Valid
- A Sudoku is valid if and only if
it has a unique solution.
-
Value
- An alias used for
digit.
-
Veracity
- See:
Verity.
-
Verity
- A statement which is true for all
alternatives in a limited set.
W
-
Walkthrough | Walkthru
- An alias used for
Solving path.
- Weak Inference
- see:
Inference
-
Weak link
- A link between 2 peers or 2 candidates
in a single cell.
-
Windoku |
NRC-Sudoku
- A
Sudoku variant with 4 extra "windows", and each window must
also contain the
digits 1 to 9.
-
WXYZ-Wing
- An extension of
XYZ-Wing to 4 cells.
X
-
X-Cycle
- A loop containing candidates for a
single digit.
- See also:
Fishy Cycle
-
X-Wing
- A
fish of size 2.
-
XY-Chain
- A chain of cells with 2 candidates
each.
-
XY-Wing
- A short
XY-Chain with only 3 cells.
-
XYZ-Wing
- A variation of
XY-Wing that has an extra candidate in the pivot cell.
-
XYZW-Wing
- Alias for
WXYZ-Wing.
Y
-
Y-Wing
- An alias used for
XY-Wing.
|
Sudoku Guides
It should be noted that a number of guides are a bit dated. For
the newest developments of Sudoku techniques, please see the Sudoku
forums.Online
Guides that are available online for free.
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