In Heyawake, the goal is to color squares white or black in order to satisfy the goals of the game (see Rules tab). To play, you can use the mouse or button and arrow keys to change cell colors:

• A mouse left-click turns a cell black, a right-click turns it to white, or a middle-click turns it back to the default gray indeterminate state.
• Once the mouse is pressed down, you can drag the mouse to set multiple squares in one drawing.
• In addition, you can use the arrow keys to move around the board, and then press keys to set cell colors.
• Press the space bar to toggle between the states, or the '1' key to turn black, the '0' key to turn white, or the backspace key to set back to indeterminate.

In Assist Mode (0), the default, only the existance of errors or incomplete rooms is indicated. In Assist Mode (1), the number of errors and incomplete rooms is indicated, see game rules. In Assist Mode (2), errors are highlighted with digit colors, and completed rules are highlighted with tile colors. In some cases the solve difficulty will greatly decrease in Assist Mode (2), so select depending upon the level of challenge desired. The canvas border will turn green if the grid is completed without error. You can press the "undo" button on the bottom of the page to undo previous moves.

Below, enter puzzle code (0-0) for one of a list of pre-defined puzzles, or a puzzle descriptor (see "Puzzles" tab). Puzzle code 0 shows an example completed puzzle that can be helpful. The following puzzle codes have demos, which will walk you through a solve to help you on the path to mastery: []).

Heyawake (へやわけ, or "divided rooms") is a classic Japanese logic puzzle published by Nikoli. In Heyawake, the puzzle board is divided into rectangular rooms, some with digits within them, and some without. The rules relate to these digits and the size and shape of the rooms with respect to their neighbors.

1. A room with a number within its borders indicates how many black cells must be within the room. Rooms without borders can have any otherwise legal number of black cells.
2. Two black squares can not touch adjacently, diagonally is ok.
3. A contiguous sequence of white cells can not extend into three consecutive rooms, either horizontally or vertically.
4. The enabled (white) cells must all form one contiguous "river" of cells, connected to each other in the vertical or horizontal direction. A river is not considered connected if it only flows through diagonally adjacent white cells.

Below select puzzle 0 to see a completed sample grid. See the Game Play or Puzzles tab for how to invoke a demo.

Puzzles can be invoked by either a numerical entry from 0-0, or through a character description of the puzzle itself, entered into the Display form on the 'Game Play' tab. The numbered puzzles are hand-crafted of varying difficulty, roughly easy to hard. Puzzle 0 shows a completed correct puzzle.

To describe a puzzle, the character string must be of the form: "WxH:<room-descriptors>", where W is a number indicating the width of the grid, and H the height. The room descriptors are a description of the individual rooms with a 5-character code for each room including, in order, yxhwd where y,x describes the starting location and h,w describes the room's width and height. The puzzle matrix should be thought of as starting at 0,0 in the top left corner, with y increasing down, and x increasing across. The value d is the count of black cells expected for the room. If there is no value, then the character '-' should be used instead. Values greater than 9 should use a-z to represent 10-35. For instance a 2-digit 2-high 3-wide room at y,x coordinate location 12,3 should be designated as 'c3232'. An example descriptor is as follows for entry 1: 'descr'. If the board is blank, there are likely descriptor errors that can be debugged by pressing F12 to see the javascript error output.

For Heyawake there are 1 demo puzzles that can be helpful to walk through solving methods. They are puzzle codes []. Enter them in the Game Play tab with the code number and there will be added a demo panel to help with the solve.

This playground was written using javascript and is available open source. All code is checked into the github repo at ohmec/puzzles. Feel free to file bugs there!