Here's a hard sudoku

Just found this one I used to test a sudoku-solving program about 4 years ago.  There is a singular solution but it took around 2 minutes to find with my algorithms.

9 4 1 5 2 8 3 5 7 1 9 2 2 4 3 8 7 6 4 1 9

Feel free to give it a go.

An explanation

I thought it would be a good idea if I wrote down what’s on my mind at the moment.  It should explain why I am defaulting to sad and not happy, why I can seem a little distracted, why I seem not to care about things I used to care about and why I’m not [...]

ipv6 ready