A Sikaku puzzle consists of a square or rectangular grid in which some of the cells contain a one or two digit number. To complete the puzzle, a Solver must divide the puzzle into a number of rectangles so that each rectangle contains exactly one of the numbers, and that number must be equal to the area of the rectangle which contains it. Each puzzle has a unique solution which does no require any guesswork to achieve.

The following graphics show a Sikaku puzzle in the Crossword Express Solve screen and a PNG graphic file produced by the program's print function, showing the complete puzzle solution. See also a  full size version of a PDF file  containing the solution.

The key features of the Crossword Express Sikaku Construction function are as follows:-
  • Fully automatic construction of puzzles.

  • Puzzles may be built in sizes ranging up to 20x20.

  • A multi-build function allows the construction of many puzzles (thousands if necessary) in a single operation.

  • Fully manual construction is also available. This allows puzzles found in the printed media to be entered into Crossword Express.

  • Puzzles can be printed in an unprecedented range of user controlled colors and formats. Output can be sent direct to the printer or, if you install the appropriate software, it can be sent to a PDF file. The recommended software for this purpose is  Primo PDF which you can download free from their website,  although you might consider sending them a small donation if you find their program useful. Mac users will be able to create a PDF file directly from the screen provided by the printer driver.

  • Formatted output can also be exported from the Print screen to graphic files which conform to the BMP, GIF, JPG or PNG formats.

  • A fully interactive Solve function is available to allow you to solve the puzzles "on screen" without needing to print them.