Friday, 15 January 2016

Avoiding vascular dementia


Diabetes increases the risk of vascular dementia. I fight this with the occasional puzzle.  Ok, I admit it, I do the diabolical from sudokuoftheday.com every day. The puzzle from last Tuesday (12 January 2016) is rated diabolical with a difficulty of 17,500. The published solution uses the forcing chain technique on two occasions. 

Can you spot the simple shortcut that solves this puzzle in a few minutes, without the use of forcing chains, guesswork, multiple path analysis, swordfish or any other convoluted technique?

Answer in a few weeks.

ps Howard from sudokuoftheday.com has confirmed the validity of my method.


Added note The diabolical sudokus of 17.1.16 (rating11700) and 21.1.16 (rating 24100) can also be solved by the application of simple logic, without the use of forcing chains.