Ghost Sudoku (26 page)

Here’s a sample of image sudoku. Given the nonpuzzle constraints of paper quality and size, I can’t bring on the hunks or the babes. But I can offer some connection with the numbers you know and love.

The faces may be different, but the rules remain the same. Looking across the middle set of boxes, you should quickly spot that the two black circles eliminate all but one space in the left-middle box, forcing the placement of a black circle, as shown.

In that same row of boxes, white stars in the center-left and center-right boxes preclude the placement of any stars in the central box except for two spaces. The position of a third star in the top-center box eliminates one of those spaces, forcing the placement of a star as shown.

Looking up and down the center tier of boxes shows a similar situation. Hexagons in the top-center and bottom-center boxes allow only two spaces in the central box, and a hexagon in the right-center box cuts down those possible spaces to just one, as shown.

However, the placement of that hexagon creates another force play, this time in the middle-left box. The newly placed hexagon eliminates the two open spaces in the top row of the box while the hexagon in the lower-left box eliminated one of the two remaining possible open spaces. That forces the placement of another hexagon as shown.

That’s it for turning up any hidden singles. The next step is to start listing the candidates for each space, with an eye toward whittling those possibilities down.

Here’s one of the drawbacks to doing image sudoku in a small puzzle format. If writing tiny numbers is a cause for eyestrain, drawing tiny symbols is completely ridiculous. Instead, I’ve opted to use the dot notation we’ve discussed in prior columns. I think you’ll be able to hook up which dot represents which symbol.

No sooner have we got everything listed than we spot a space with only one possible candidate—a dark star—for Column 1, Row 6, in the left-middle box, which we’ve starred. This starts a chain reaction, deleting a dark star in Column 1, Row 4, two spaces above, establishing the sunburst as the only possible candidate there (another star). Furthermore, that deletes the possible sunburst next door in Column 2, Row 4, leaving the spiral as the final candidate standing with another star.

That actually solves out the entire box, as the next diagram shows.

However, the chain reaction continues to rumble along. Look along Row 4 to the intersection with Column 8. The placement of a spiral six spaces back eliminates the spiral candidate here, leaving only the dot for the crossed arrows, which we’ve starred. One space farther along the row in Column 9, crossing out the arrow dot leaves only the candidate for the pair of bars, which we’ve starred.

But then, five spaces to the left in Row 4, Column 4, eliminating the representative for the bars leaves another single candidate—this time for the dark star. Guess what? That actually clears the whole row.

Are the aftershocks finished? Why, no! Here’s a cleaned-up version of the puzzle:

Moving up from Row 4 along Column 1, we encounter yet another single candidate at Row 2, which we’ve starred. That establishes the triangle in that space, eliminating three candidate spots in the upper-left-hand box and four more along the row.

Meanwhile, take a look at the last two spaces in Row 6—we’ve starred a naked pair sitting brazenly out there. (Okay, there are easier techniques to use, but they stood out, so I’m using them.) Since the spaces share candidate spots for the triangle and the spiral, those symbols can only be found there for the row. That means farther to the left at Row 6, Column 4, we can eliminate the dots representing the spiral and the triangle, leaving only the crossed arrows in control of the space. (As a matter of fact, this is the only remaining dot for that symbol in the row.)

That naked pair isn’t done, however. The triangle-spiral duo prohibits the placement of those symbols anywhere in the middle-right-hand box. In this case that boils down to Row 5, Column 7. Crossing out the candidates for the “taken” symbols leaves only one representative there—the sunburst.