Abstract: An apparatus and method to solve sudoku. A gameboard contains a sudoku grid, with its rows, columns, and boxes identified, and means of mutually distinguishing its boxes. A group of tokens corresponding to each box is provided, along with means to associate each group of tokens within a unique box. Setup tokens are emplaced on the gameboard to mirror the setup identifiers of a sudoku puzzle to be solved. Then tokens are emplaced in home cells, straddling cells they could possibly wind up in, at or straddling heads or feet of rows or columns they may end up in, or off-board in queue waiting movement to a more defined position. A breakthrough board is disclosed wherein possible token positions may be erasably inscribed. A method to return the gameboard to pre-trial-and-error configuration using the breakthrough board is disclosed.