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Sat, 24 Aug 2019

iDoku Solving Tips

iDoku is a variant of ordinary sudoku that appears in the new 'i' newspaper.

The aim of iDoku is to fill each row, column and 3x3 box in the puzzle such that 1 - 9 appear once only in each of them. In addition, there is a grey capital 'I' shape in the middle of the grid, covering nine cells, and crucially these too must contain 1 - 9 once only.

The key to solving iDoku as opposed to ordinary sudoku is to remember that extra regions exists, that there are 28 regions in the puzzle rather than the usual 27 of a standard 9 x 9 puzzle.

If you don't consider the central grey I, after the name of the newspaper, then you won't be able to solve all but the easiest iDoku puzzle.

The central 'I' behaves the same as any other region in the puzzle, so if there is a '1' in the first cell of the 'I' shape at the top left, then this means that none of the other eight cells can contain a '1'.

Once you get the hang of this rule and eliminating values that appear in the 'I', then you can continue to solve iDoku puzzles as you would a normal puzzle.

You'll never need to guess when solving an iDoku as logical rules can be used at all times to make progress, and you can use the same types of logic as you would when solving an ordinary sudoku puzzle.

If you have any questions about iDoku then please do post them below. Have you played the puzzle in the new I newspaper?
Date written: 19 Nov 2010

Category: sudoku

Keywords: idoku


Havent tried idoku yet!
By: William - 15 Jul 2012 23:26:38

Where are the answers to the daily iduko please?
By: Ruth - 15 Jul 2015 12:41:25

You can find the daily solutions at: The I puzzles Solution Page
By: Clarity Media - 27 Jan 2017 12:57:49

Please send me a link to the solution got the iduko set on Thursday 6th April 2017.
By: Gordon Beastall - 08 Apr 2017 11:21:25

Hi Gordon, if you visit: The Solutions Page and scroll down to the bottom of the page, you can view solutions for 6th April 2017, assuming you do so within 10 days from the date of publication. Hope this helps!
By: Clarity Media - 08 Apr 2017 19:58:06

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