In today’s product review, we explore a clever and intriguing puzzle in the Sudoku vein: the Pentdoku puzzle. As you might’ve deduced from the name, pentdoku puzzles only use the numbers 1 through 5, but the unique design and less traditional solving rules make for a curious and more demanding solve than you’d expect.

Creator Dale Maron provided me with a copy of the first volume of his Pentdoku Puzzles collections. You would think that almost halving the number of options in a regular Sudoku would make this puzzle easier, but these puzzles offer just as much challenge, if not more, than the average Sudoku.

Let’s take a closer look at one of these colorful puzzles.

It’s essentially two puzzles in one, as the outer ring of pentagons is separate from the inner ring. Neighboring numbers in the outer and inner rings can be the same, which is an important distinction when it comes to solving. (As you can see in the upper left, where a 5 in the outer ring neighbors a 5 in the inner ring.)

You must place the numbers 1 through 5 in each of the pentagons in the inner ring. As you can see, each pentagon shares two triangle boxes with its neighbor on the left and two triangle boxes with its neighbor on the right. Standard Sudoku rules apply here, so no two neighboring boxes can have the same number inside.

You must also place the numbers 1 through 5 in each of the pentagons in the outer ring, and again, standard Sudoku rules apply. But unlike the inside ring of pentagons, there are no overlapping sections here. So how do you deduce where to place the other numbers?

That’s where the second rule of the outer ring comes in. Each six-block run like the one highlighted in green — which I think of as Batman symbols — not only contains all five digits 1 through 5, but they begin AND end with the same number.

So, in this particular Batman symbol, we know that it will both begin and end with a 3, and the numbers 1, 2, 4, and 5 will appear in some order between the two 3s.

But what about those shaded triangles scattered throughout the grid? Those are the only interaction between the inner and outer rings. The same number will appear in both yellow triangles, and that goes for the red and green triangles as well. And those little triangles often prove to be a huge solving aid in these puzzles.

With differing designs allowing for more open or more dense pentagon arrangements, there’s enough variety and challenge in this collection to keep solvers happy. And quite honestly, I liked having a brand of Sudoku that pushed me outside of my usual solving comfort zone. Moving away from the standard rows and columns layout had my brain working overtime to adapt to these new grids, and that is a big plus in my book.

My only caveat is that there are a few printing issues with the book. There are two blank pages where puzzles should be, and several blank pages in the back where some of the puzzle solutions should be.

You can check out Pentdoku Puzzles: Volume 1 in our Holiday Puzzly Gift Guide or on the Outskirts Press website, as well as all things Pentdoku at Dale’s website pentdokupuzzles.com. Thank you to Dale and Sonya for the opportunity to try out Pentdoku Puzzles!

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