Sci-doku is Sudoku with Letters

If you like doing Sudoku puzzles, you will like this variant of the puzzle by Scientific American known as “Sci-doku”. It uses letters instead of numbers. As with normal sudoku, each row, column, and nine-cell grid must contain one and only one of the nine letters. You can not just use any nine letters, you have to use the letters that are already shown on the grid.

Here are the full rules.

Play the Sci-doku games on Scientific American website »

Play Games Online at

You can play free online games at You can purchase a license to have the game be placed on your site.

You can buy the Flash source code (the FLA files) so that you can reprogram or customize the game (if you are a Flash developer).

Or you can have them build a custom game for you.

Video On How To Solve KenKen Puzzles

Puzzle-master Will Shortz of NPR radio will introduce us on the rules of KenKen puzzles and how to solve them.

The above video was showing a KenKen that only uses the add operation of the digits. However, general KenKen puzzles have add, minus, multiply, and divisor operators indicated next the results number within their cages. The below video shows how to work out these more difficult forms of the puzzles.

Play KenKen Puzzle Online

Start with an easy KenKen which is a 4×4 grid.

How to Play KenKen

See video that gives you a quick summary of the game and how to play and solve them.

Basically, you have a square grid of cells. You put a digit into each cell. The digits are 1, 2, 3, etc. up to the size of the grid. So for a 4×4 grid above, you can only use the digits 1, 2, 3, and 4. For a 6×6 grid below, you can use the digits from 1 to 6.

You will notices that cells are grouped into “cages” as denoted by their darken outlines. Each cage as a number with a mathematical symbol. The digits that you put in the cells must result in that number if you apply the mathematical operation on the digits. Furthermore, any row or column in the overall grid can not have a repeating digit.

KenKen Strategy

So the strategy is to use the above constraint rules to eliminate which digit can not go into each cell. This game is basically a process of elimination. Start working on the smaller cages first. That way fewer possible digits can go into them. One you have filled in the smaller cages, the digit in there will constraint what digits you can put in the other rows and columns.

More difficult 6×6 KenKen

Once you’ve mastered the strategy of KenKen, try a more difficult 6×6 KenKen grid …

Have fun.

Play Sudoku Online

You can play Sudoku online here (courtesy of Fill in the squares of the grid with numbers from 1 to 9. Make sure there are no duplicate numbers in any rows, columns, or any of the nine smaller inner 3×3 grids. You can select the difficulty level.

Bubble Sokoban Online Game

Found this Flash puzzle game on

You move a person around in a grid with obstructions. Your goal is to push the movable block into the highlight squares. Plan your move carefully. Because you might push the blocks into an orientation where you can not solve the puzzle.