Hanjie is a Japanese puzzle often described as the thinking personís painting by numbers. The aim is to fill certain cells in the grid to form a pixelated picture.
The only clues provided are numbers at the end of each line. By taking a logical approach to these clues, the solver is able to deduce which cells should be filled and which should remain empty. Gradually, a picture takes shape.
As with all the best puzzles, the rules are quite short and simple: fill cells in each row and column so the arrangement and sequence of filled cells corresponds to the clues. Note that there must be at least one empty square between adjacent blocks.
For example, given the clues 2 6 for a row, the solver knows that the row contains a block of two shaded cells and a block of six shaded cells; the solver knows, too, that there is at least one empty cell between these blocks.
For more details and an interactive tutorial, see the Puzzler Encyclopedia.