How To: Solve KenKen puzzles with Will Shortz

Toss aside that Sudoku. Take a stab at the new craze to hit the Times: KenKen.

New York Times puzzle editor Will Shortz introduces KenKen and gives a brief play-by-play demonstration of this new puzzle craze.

In this video, Will Shortz speaks about how he found out about and fell in love with KenKen. He also give a brief, step-by-step demonstration of how to solve a KenKen puzzle.

Here's the basic KenKen description. (Shortz offers a video tutorial on a simple puzzle that's also helpful.) It's got square puzzle grids--3x3 is the easiest, and the largest I've tackled is 9x9. In general, the larger the grid, the harder the puzzle, though several other elements factor into the difficulty.

As with Sudoku, each horizontal row and vertical column gets each number exactly once, but you have to figure out the proper places. With a 3x3 grid, each row and column has the numbers 1, 2, and 3. With a 6x6 puzzle, the numbers range from 1 to 6, and so on.

So where's the math fit in? Various groups of boxes are surrounded by a bold line, called a cage. A cage can be horizontal or vertical, but it also can span multiple rows and columns if it's L-shaped or square, for example.

Each cage contains a number and the mathematical operator. To fill the cells in the cage, you must combine the numbers in the cells using the operator. For example, a two-cell cage with the number 3 and a plus sign means that the two unknown numbers must be added together to produce 3. That means one is a 1 and the other a 2, but you have to figure out which goes where.