Summer Sudoku is heating up with Hard Sudoku, and this game is surely only for seasoned Summer Sudoku players who love a good challenge. Hard sudoku is played just like all easier sudoku boards before it – place the digits one to nine into all the columns, rows, and 3x3 boxes on the sudoku board only once. Hard Sudoku is named as such because answers will not always be easily evident at this level of sudoku play. You may need to employ more advanced techniques of pattern finding in order to whittle away at the possibilities of numbers each block on the sudoku game board can hold. Hints will be crucial from this point forward, so be sure to use the pencil in the bottom right corner to activate sudoku note taking.