I've recently launched a new series of '101 Giant Sudoku' books, to cater for those who like their Sudoku to be considerably larger than normal!

You can see the entire series at PuzzleBooks.org (scroll to the bottom) or visit Amazon and search for "101 giant sudoku".

There are 12 books in the series: 14x14, 15x15, 16x16, 18x18, 20x20, 21x21, 22x22, 24x24, 25x25, 28x28, 30x30 and 36x36.

In Sudoku 36x36, for example, you must place 0-9 and A-Z into every one of the 36 rows, 36 columns and 36 6x6 boxes!

As you might hope, these puzzles are designed so they don't need any advanced logic - just scanning of the rows and columns and boxes to see what's missing and what can fit where.

All the puzzles are designed with attractive 8-way symmetry patterns.

In 36*36 sudoku it will really tough to manage all numbers and alphabets. It needs lots of mental exercise.