## multiplayer sudoku

Everything about Sudoku that doesn't fit in one of the other sections

### multiplayer sudoku

Hi,
Does anybody know about multiplayer variants of sudoku.
Does anybody have ideas?

BTW Same question was asked here
http://www.setbb.com/phpbb/viewtopic.php?p=286&mforum=sudoku
evert

Posts: 186
Joined: 26 August 2005

I'll have a think but I'm pretty sure that any multi-player game you invent will be a 'draw' between when there are half-decent players playing, so it would probably have to be restricted to whoever finishes the puzzle first. I suppose this would be an online, real-time competition which already exist on a lot of puzzle websites.

G
george-no1

Posts: 150
Joined: 20 May 2005

I heard an idea for a 2-player game whereby you gat a regular puzzle (probably needs to be a fairly hard one), and players take yurns to put numbers in. The loser is the first player to be forced to put a number in which is in the same row/column/box as another one of that number. So you can put in numbers on your turn that you know to be wrong if you like, as long as they're note immediate violations of the sudoku rule. I have no idea if it'd be any good, though.
PaulIQ164

Posts: 533
Joined: 16 July 2005

But if you're allowed to put wrong numbers in, then the sudoku never gets completed, so it's not a sudoku.

Surely the winner is predetermined before the game starts (by the numbers that are already in the grid) (unless someone makes a mistake)?

I'm not saying your idea is bad, it has the principles of something good but it's not watertight. Maybe designing a multi-player game could be a project for the users of this forum?

G
george-no1

Posts: 150
Joined: 20 May 2005

After some brainstorming I thought about the possibility that
2 players are solving the same sudoku with each of them having
limited knowledge of all the necessary clues.
-although all the clues of the puzzle are known to at least
1 of the players.

Filling the cells in turn they sometimes must pass there turn
because the opponent needs to come up with required information.
evert

Posts: 186
Joined: 26 August 2005

Ooh! How about, a sudoku that players take turns to fill in, one number at a time, and each number they put in, they get that many points? So there might be, say, a really obvious 1 to place, but maybe if you look harder you can find a 9 and score big!

Edit: to add an extra layer of complexity, you could have a rule where you can place more than one number on your go if they're all the same digit. So you have to be careful not to leave your opponent a situation where they can place a whole lot of 7s (or whatever).
PaulIQ164

Posts: 533
Joined: 16 July 2005

Yes, that's a much better idea, Paul. However, there would have to be some sort of time limit otherwise people would look for 9s for a long time instead of taking the obvious 3, for instance. Also, the sudoku itself would have to be chosen carefully otherwise the person going first could end up getting 36 points before anyone else has had a chance. This second problem may lead to the conclusion that the sudoku used cannot just be randomly chosen by a computer, which might scupper the whole idea.

G
george-no1

Posts: 150
Joined: 20 May 2005

Well, I have a rough Idea for a game which hasn't been tested:

Take a pack of cards, including 2 jokers, and deal them out like this: (Edit: Made neater)
Code: Select all
`OOO|OOO|OOOO  |   |  OO O|OOO|O O---+---+---O O|   |O OO O|   |O OO O|   |O O---+---+---O O|OOO|O OO  |   |  OOOO|OOO|OOO`

Then the players take it in turns to place 5 of the remaining cards face-down on the board. The last card is flip, and if it is a 1-9, then the next player can place it anywhere.

Then, in turn, the players flip the cards over in any order they choose. If a card is 10-K, then it becomes a blank. A Joker becomes a number of that player's choice. A 1-9 becomes that number, unless the sudoku rules dictate that it can't be placed there, when it becomes a blank.

The players then take it in turns to place a number on the grid, following the basic rules of no repeating numbers. If a player can't place a number (either because the grid is full, or because all remaining cells have been killed) then he loses the game.

Any thoughts?

LA
Last edited by Lardarse on Sat Sep 03, 2005 9:16 am, edited 1 time in total.
Lardarse

Posts: 106
Joined: 01 July 2005

i like landarse's idea with cards however there would need to be some kind of time limit, also there would have to be a referee with the solution to see if the one they place is right

an idea for an online computer game:
Both players have a screen withe the puzzle on it and are both doing the puzzle at the same time, when a player puts a number in then they would get one point and then that number would appear on both screens, when the puzzle is completed then the player who placed the most numbers would win.

If an incorrect number was inserted it would not be filled in on the grid and the player who placed it would loose 10 points
Pi

Posts: 389
Joined: 27 May 2005

I tested in fact the version of Pi more or less - with a friend both using
pencil and paper.
Very nice and lots of fun!

However I'm looking for a more fundamental change
of sudoku rules towards multi player situation.
evert

Posts: 186
Joined: 26 August 2005

There is a fellow Norwegian who has posted his version of a multiplayer game on his website. Can be found here: http://www.menneske.no/sudokuto/

I haven't tried it, but would like to hear more about it.
noggi

Posts: 11
Joined: 26 July 2005

uhh can't you just race each other? not nine by nine but i've played some sudoku puzzles that are 20by20 takes 30 min or more...
123HI

Posts: 4
Joined: 02 September 2005

Pi wrote:i like landarse's idea with cards however there would need to be some kind of time limit, also there would have to be a referee with the solution to see if the one they place is right

Firstly, it's not an N

And secondly, the idea isn't to put numbers in the correct places. The idea is to leave your opponent with nowhere that they can put a number. This includes leaving cells with no possible solution. In fact, 1 player will likely have to do this, and then the other will likely have to do this as well.

I dealt some cards out, and my guess is that you will have about 30 numbers in the grid when the cards are all flipped.

LA
Lardarse

Posts: 106
Joined: 01 July 2005

Here's a set-up that was generated by this method:
Code: Select all
` 17| 3 |  46  |   |   8  |9 6|3 5---+---+---7  |3  |1  3  | 1 |4 8 84|2  |6  ---+---+---  6| 52|      |   |   9 5| 71| 2 `

It's probably non-unique though...

I tried the online game that noggi posted, and noticed that it had several of the blocking ideas that my game has, except that it starts completely empty, which I think slows the game down. My game could possibly be modified to work better on a computer. But I'll let someone else play with that idea...

LA

Edit: Missed a 4...
Edit2: Dupliccate 7 in row 4. Can some1 write a computer program to do this please?
Lardarse

Posts: 106
Joined: 01 July 2005

### SuDoKu - Battle Lines

If you want to play an actual multiplayer game, try the new board game called SuDoKu - Battle Lines.
Details can be found at ratkins.com.
FoxHatzi

Posts: 7
Joined: 07 September 2005