# Sudoku

## Sudoku is a number-placement game. The object is to fill out the nine-by-nine grids with numbers that do not repeat on both the row and column of the grid.

###### Asked in Sudoku

### What is sudoku?

Sudoku is a puzzle with 9 rows and columns. The rows/columns are
divided into 9 3x3 squares (you'll notice the bold lines; those are
the things that separate the 3x3 squares.) that are indicated in
bold lines. There are many kinds of sudoku. Sudoku was originally
called Number Place.
It originated in Japan, hence the name, and was a challenge
similar to crossword puzzles, which don't work well with kanji.

###### Asked in Sudoku

### Should you ever have to guess in sudoku?

No, you are supposed to use logic deduction to come up with the
friendus.
It can seem impossible at times, but a sudoku should always be
solvable using logic reasoning.
Though a puzzle SHOULD be solvable using this technique , it is
not always possible in more advanced puzzles. The most difficult
levels require you to assume that a box is filled with one number
or another. You pick one of the numbers, and then, you must follow
the puzzle until you either solve it, or come to a impossible
situation. Using the logical reasoning of "reductio ad absurdum",
you then conclude that the number you picked WASN'T the correct
number and start over from that junction point.

###### Asked in Inventions, Sudoku

### Where was sudoku invented?

###### Asked in Algebra, Sudoku

### How many possible solutions are there for a single sudoku game?

Any given Sudoku puzzle has just one solution. This is so long
as the puzzle already comes with at least 17 digits already placed
on the grid. If there are any less than 17 digits, then the puzzle
has more than one possible solution, and therefore cannot be solved
properly. The total number of possible combinations of digits on a
standard sudoku grid is 6,670,903,752,021,072,936,960. However it
can be argued that many of these combinations could be the same as
another, only backwards or rotated. Factoring out all logical
duplicates, the number of possible combinations drops to 3,359,232.
This is essentially the total number of possible sudoku puzzles. *
My Friend Dev Oneal has completed an 'Impossible Level' Sudoku
puzzle, as I checked the answer given by the "Auto-Solve" feature
and compare with his solution and have found both was correct but
with different pattern. Hence, it could have more than 1 correct
answer.

###### Asked in Basketball, Psychology, Sudoku, Counter Strike

### What are the advantages of playing Sudoku?

For example, have you ever watched TV and someone tried talking
to you but you were in a zone? You didnt respond or realize they
were talking. These "zombie" like trances are deleted eventually
from your behavior if your mind exercises extensively. Sudoku is a
stimulating and difficult mind exercise that can be extremely easy
to those that just automatically figure the pattern in their mind.
Those people are less likely to become "zombies". This takes years
and years of dedication and not just with sudoku, but hundreds of
thousands of mind boggeling puzzles.

###### Asked in Fashion Design, Sudoku, Crossword Puzzles

### What is the best way to do a crossword puzzle?

CAUTION: If you're working on the New York Times puzzle for July
15 2007, I use some examples in the material below.
I LOVE crossword puzzles and I do them daily. It's a joy when I
finish one (I don't always...) There are some general ideas that I
use, but it is mostly a matter of practice, and starting with
puzzles that are not extremely difficult. First, use a pencil with
an eraser. Go through the whole puzzle and get the 'easy' items you
mentioned above. Never, never assume that the wonderful answer you
just entered, you know, the one that shows what a good puzzler you
are-- never assume that it is correct, and CANNOT be
changed. Usually, when I trip up on a puzzle, it's because I
won't let go of that 'special' answer that I KNOW is right, because
I'm so darn clever. Be willing to let it go. I will often erase a
word, just to clear my mind. This sometimes helps me solve
connected words, even if the word I erased turns out to be right. I
put it back in. Say that you have a word in mind, but you are iffy
about it. Keeping the letters in mind, go through the 'across'
clues to see if the letters you have in mind will bring quick
friendus to any of those. Example: The clue for 63 across is:
"Showing deep embarrassment". I'm thinking of entering the word
CRIMSON, but... I don't know... When I look at the clue for 63
down, "Like new bills", 5 letters, I think: If it begins with "C",
hmm... "CRISP"! I think of this as evidence that "CRIMSON" might be
right. Skipping to 65 down, the word beginning with "I" 5 letters,
the clue is "Atahualpa's people". I think: Atahualpa sounds
Mexican, or central American. Hmmm. Maybe a historic group,
beginning with "I", 5 letters. I don't really know for sure, but I
see that "INCA" fits. So I go ahead and put it all in. You don't
really have to KNOW all the information. You just get good at
making far-reaching, and sometimes weird connections. It's all part
of the fun. I actually "know" maybe 10% or 20% of the information
in a puzzle, even a puzzle I finish correctly. If I can't find any
"evidence" that the word I have in mind might be right, I usually
don't put it in. I have to feel comfortable with 2 or 3 "evidence"
words, depending on the length of the word I have in mind. Clues
that have question marks at the end have to be treated with special
care. The question mark means that the clue is a TRICK. Sometimes
(not always) the trick is associated with the puzzle's 'theme'.
Here's the clue: "Hogwarts?" 18 letters. The clue invites me to
think about Harry Potter, the movies, the characters, the plots,
the "stuff", and all of that throws me off. It's not going to be
that obvious. The answer is "INVOCATIONALSCHOOL". People who write
these puzzles are DEVIOUS, maybe even EVIL. They want you to sweat,
and work for success. A play on "Vocational School", and
"Invocation". Sometimes the tricks have to do with how you read the
clue-- Clue: "All your work may go into it". Answer: RESUME. If the
clue itself contains an abbreviation, it is a hint that the answer
may be an abbreviation. If the clue is asking for something in the
past tense, the answer will be a verb in the past tense. Tense will
match from clue to answer. These are just a few ideas. Keep
practicing, and be sure to check the friendus when you get them. As
you check the friendus, play with them in your head. Imagine how
knowing that one word might have lead you to the others. Don't give
up... You'll get a lifetime of pleasure from puzzling, and it will
help keep your mind sharp!

###### Asked in Sudoku

### Where did Sudoku come from?

###### Asked in Sudoku

### What are the rules of sudoku?

###### Asked in Brain Teasers and Logic Puzzles, Sudoku

### Is there a way to solve Sudoku puzzles-like a pattern?

Well, there is a pattern to all of them... only one of each
number in each column and in each row, and in each of the nine
subareas. That's how you figure them out, by evaluating what could
go in each square until you have it narrowed down and can be sure
that only one number fits in a certain place... then you look for
another, because hopefully that new number helped you narrow things
down further, etc.

###### Asked in Sudoku

### What is SUDOKU techniques?

###### Asked in Chimpanzees, Sudoku, Mathematicians

### What are the kinds of sudoku?

SUDOKU or Single Number, is a Japanese number puzzle that has
swept through the world with the same gusto as the Rubiks Cube.
Newspapers carry it, software houses, toyshops and bookshops sell a
great deal of it. There is even a world championships. In the basic
form it is a nine-by-nine grid divided into nine (sub-set) squares
of nine squares. Numbers between one and nine are strategically
placed by the compiler and the player is invited to fill in the
rest. The rules are very simple, the game is incredibly addictive.
Fill in all the squares with one number each of one to nine. There
are to be no repeated numbers in any vertical or horizontal line
nor a repeated number in any sub set (square) of nine squares. How
hard can it be? Common variations of Sudoku are 8x8, 12x12 and
16x16 squares. Letters or shapes can be substituted for numbers.
Other Japanese number puzzles include Kakuro, Kokonotsu, Kikagaku,
Samu.

###### Asked in Sudoku

### How can you learn to create sudoku puzzles by hand?

I certainly wouldn't recommend this for casual puzzle makers. It
is incredibly tedious. Start with filling in a grid in such a way
as to have the finished Sudoku result of only 1 instance of each
number in a row, column and box. Double check your work carefully,
as a mistake at this point will invalidate the entire puzzle! Start
anywhere you like, and delete ONE number. Using "reverse Sudoku
logic", erase another number that can be proven to be the only
number that could go in the square that you erase. Keep erasing
numbers that you can "provably show to be the only number that
could go in the square given the 'current' state of the board AFTER
you erase the number". When you can't figure out a way to erase any
more numbers (not enough clues to force a move), you are done!

###### Asked in Math and Arithmetic, Sudoku

### Is sudoku a mathematical game?

Yes. Sudoku is a mathematical game. Actually, I would not
consider Sudoku a "mathematical" game ... it does however use some
of the same logical problem-solving strategies that are applied in
finding solutions to many mathematical problems. I teach middle
school math and have found that some of my students who would
rather skip the dreaded math class, are able to complete (and even
enjoy!!!) Sudoku puzzles. :o)