GB2427569A - Apparatus for assisting in the solving of Sudoku puzzles - Google Patents

Abstract

A board game is disclosed for solving Sudoku puzzles. The game comprises a board 100 defining a matrix of squares 102 and a plurality of numbered counters 104 for placing on the squares. The counters are double sided. The opposite sides of each counter display the same number but are distinguishable from one another.

Description

BOARD GAME

Field of the invention

The present invention relates to a board game for assisting in solving Sudoku puzzles.

Background of the invention

The game of Sudoku, which originated in Japan, has acquired a large following in many countries, with several newspapers publishing a daily Sudoku puzzle, alongside crossword and other puzzles.

The original puzzle is solved by populating squares in a matrix with the numbers 1 to 9. The matrix is a nine by nine matrix which is itself subdivided into nine contiguous three by three matrices. A correct solution to the puzzle is one in which no number appears more than once along any vertical or horizontal line and no number appears twice in any one of the smaller three by three matrices.

There are variations on the puzzle using a smaller or larger range of numbers, the number of squares in the matrices being correspondingly increased. The large matrix is always square but the smaller matrices need not be square. For example, each smaller matrix may have four by three squares and the larger matrix may be made up of twelve of the smaller matrices arranged in a three by four array.

Such puzzles are normally solved using pen and paper and players use the squares already populated to determine if there is a square which can only accept one number. With more difficult puzzles, players can reach a point when they cannot identify any one square that can only accept one of the possible numbers and they are obliged to guess.

When using pen and paper, problems occur when trying to retrace one's steps if a guess turns out to be incorrect. In such an event, one needs to remember all the squares that were populated on the assumption of the guess being correct and crossing out the incorrect squares can also be untidy and confusing.

Summary of the invention

With a view to mitigating the foregoing disadvantages, the present invention provides a board game for solving Sudoku puzzles, comprising a board defining a matrix of squares and a plurality of numbered counters for placing on the squares, wherein the counters are double sided, the opposite sides of each counter being distinguishable from one another while displaying the same number as one another.

When playing Sudoku using the board game of the invention, instead of writing numbers on paper, counters are placed on the squares of the board. The advantage offered by the use of reversible counters is that a first side of each counter is used when the solution for the relevant square of the puzzle is known to be correct and the second side is used when there is some doubt regarding the solution and a guess is being made. All counters placed on the board that are based on a previous guess being correct are likewise placed with their second side facing upwards. Should a guess prove to be incorrect, one can simply remove each of the squares displaying its second side and attempt a different solution. The ability to retrace one's steps in this way avoids the need to think several moves ahead and reduces the difficulty in finding a solution.

It should be mentioned that the term "square" is being used herein to indicate a position on a board rather than a geometrical shape. Likewise, the counters are described herein as being numbered, this being the normal way in which the game of Sudoku is played, but one may use alphabetic or other symbols to distinguish the counters from one another.

In a preferred embodiment of the invention, the board has recesses for receiving the counters, each recess corresponding to one of the squares of the matrix. Further recesses may be provided to retain counters yet to be placed on the matrix. The provision of such recesses avoids the risk of the counters being dislodged by accident. Of course, the counters need to be thicker than the depth of the recesses to allow them to be repositioned with ease.

As an alternative, or in addition, to the provision of recesses, the counters may be attracted to the board magnetically.

The simplest and most striking way of distinguishing the opposite sides of the counters from one another is to use different colours for the numbers (or other indicia) or for the background on which the numbers are written.

An advantage of the use of a board to solve Sudoku puzzles over the use of pencil and paper is that it enables puzzles to be solved by the blind and visually impaired. In such a case, braille or other markings can be used to number the counters and texture can be used to distinguish the opposite sides of the counters from one another.

The board may suitably be provided with a lid to form a box so as to prevent counters from being lost. The lid of the box may also serve to hold counters in place on the board, allowing the player to return to a partly completed puzzle.

It has previously been mentioned that variations have been proposed to the nine by nine matrix on which Sudoku was originally played. To allow the same board to be used when playing such variations, it is possible to provide a board having a large matrix and to provide a mask for placing over the board to blank out some of the squares and to demarcate the boundaries between smaller matrices into which the main matrix is subdivided.

Brief description of the drawings

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a typical Sudoku puzzle, as published daily in many newspapers, Figure 2 shows the solution to the puzzle of Figure 1, Figure 3 shows a plan view of a board game of the invention, Figure 4 shows a mask for use with the board of Figure 3 to restrict the number of used squares, Figure 5 shows the mask of Figure 4 when fitted to the board of Figure 3, and Figure 6 shows the opposite sides of one of the counters in Figure 3.

Detailed description of the invention

Figure 1 shows a typical Sudoku puzzle. A square grid made up of nine by nine squares, is subdivided by heavy lines into nine smaller grids each containing three by three squares. To solve the puzzle, one must populate the empty squares with the numbers 1 to 9 such that the same number does not occur twice in any line nor in any of the smaller three by three grids demarcated by the heavy lines. The solution to the puzzle of Figure 1 is shown in Figure 2.

When solving such a puzzle using pen and paper, one can find squares which will only validly accept one value. Thus in Figure 1, one can quickly see that the number 8 must go in the second square of the first row as it would cause a duplication if entered in any of the other squares of the top left hand grid. One can therefore confidently enter the solution for that square. Using the same logic, one can ascertain that at this stage in solving the puzzle, the last square of one of the first two rows must contain the number 2. One cannot however yet be certain which of these squares two should contain a 2. If one assumes that the 2 should go in the last square of the first row, then one can deduce that the fourth square on the second row must also be a 2 and, using similar logical processes, one can then go on to make further deductions.

If the player had guessed incorrectly and entered the 2 in the last square of the second row, it could have taken several further deductions before the player discovers that the guess was bad. In that event, if the puzzle was being solved using a pencil and paper the player would need to remember all the squares which were incorrectly populated as a result of the incorrect guess so that they could be rubbed out.

The board game of the present invention, as shown in Figure 3, comprises a board 100 having a matrix of recesses 102 for receiving numbered counters 104. The matrix is a twelve by twelve matrix, for reasons that will be explained below, but it could alternatively be a nine by nine matrix mirroring the puzzles shown in Figures 1 and 2. Each of the counters 104 is as shown in Figure 6. In particular, the counters are double sided and carry the same number on both sides, being the number 1 in Figure 6. However, the sides are distinguishable from one other, the colours of the background and foreground being reversed in the illustrated

example.

When solving a puzzle using the board and counters of Figure 3, the known squares at the commencement of a game are all populated with counters with a first orientation, say with black lettering on a white background. Squares such as the second square of the first row are likewise populated using counters of the first orientation as one is sure of the choice. However, when placing a counter with the number 2 in the last square of one of the first two rows, it would be positioned with the second orientation, to indicate that at this stage there is some doubt attached to the solution.

Should a guess later be discovered to be incorrect, one can readily identify all the wrongly populated squares from the orientation of their counters and retrace one's steps so that an alternative solution may be attempted.

The board in Figure 3 has in addition to the recesses 102, recesses 106 in which unused counters can be stacked on their edges. In this way, the game can be played with the board resting on one's lap instead of requiring a table. The board may be made attractively of wood so that it can itself be used ornarnentally, as are chess boards. Alternatively, it may be made of a metal and the counters can be held in place magnetically.

Conveniently, the board may be provided with a lid (not shown) to form a box in which the counters can be safely stored when a game is not being played. If the lid fits the board closely, it can also be used to retain counters in position so as to allow the player to return to a puzzle that has been only partially completed.

The reason for there being a greater number of squares than necessary on the board of Figure 3 is to allow variants of the game to be played using the same board. Thus, while the board of Figure 3 is designed to play a game on a twelve by twelve matrix, it can be adapted by the use of a mask to play games having matrix with fewer squares.

The mask 120 shown in Figure 4 comprises a solid sheet with six rectangular windows 122 each of a size to overlie a matrix of three by two squares. Figure 5 shows that when the mask of Figure 4 is placed over the board of Figure 3, it defines a six by six matrix formed of six smaller matrices each containing six squares. In this case, one would only use the counters numbered from 1 to 6. Likewise, a different mask can be placed over the board of Figure 3 to allow a nine by nine game of Sudoku to be played.

The bars 124 between the windows 122 of the mask 120 perform the same function as the heavy lines in Figure 1, that it so say they serve as demarcations between the smaller matrixes. If a board is not designed to receive masks, then such demarcation can be achieved by printing on the board.

Unlike the use of pencil and paper, the present invention allows Sudoku puzzles to be solved by a blind person. The counters can be numbered in braille and different textures can be used to differentiate between the orientations of the counters. Because of the board has recesses, empty squares can be ascertained by touch and the bars between the windows of the masks, or other surface features, can allow the demarcation between the smaller matrices to be determined by touch.

Claims (10)

1. A board game for solving Sudoku puzzles, comprising a board defining a matrix of squares and a plurality of numbered counters for placing on the squares, wherein the counters are double sided, the opposite sides of each counter being distinguishable from one another while displaying the same number as one another.

2. A board game as claimed in claim 1, wherein the board has recesses for receiving the counters, each recess corresponding to one of the squares of the matrix.

3. A board game as claimed in claim 2, wherein the board includes further recesses provided to retain counters yet to be placed on the matrix.

4. A board game as claimed in any preceding claim, wherein the counters are attracted to the board magnetically.

5. A board game as claimed in any preceding claim, wherein the opposite sides of the counters are distinguished from one another by the use of different colours for the numbers and/or for the background on which the numbers are written.

6. A board game as claimed in any preceding claim, wherein braille or the like tactile markings are be used to number the counters and the opposite sides of the counters are distinguishable from one another by touch.

7. A board game as claimed in any preceding claim, wherein the board is provided with a lid to form a box for storage of the counters.

8. A board game as claimed in claim 7 when appended to claim 2 or 3, wherein the lid of the box serves to hold counters in place within the recesses on the board.

9. A board game as claimed in any preceding claim, wherein a mask is provided for placing over the board to blank out some of the squares and to demarcate the boundaries between smaller matrices into which the main matrix is sub-divided.

10. A board game substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.