The World's Hardest Sudoku (June 2012)

[Zapmeister]

choofers: that's a pretty nice set of techniques you know already, you should be able to do basically every puzzle that has or ever will be published in a newspaper or book with what you know. if you want to learn something new, i suggest some guy's tutorial called Strong Links For Beginners which describes the technique known variously as "2 strong links", "turbot fish", "2-string kite", "skyskraper", etc. be warned that it's written in a slightly patronising way on purpose. by the way you may like to know the 3x3 extension of an x-wing is called a "swordfish"

igotrhythm: the thing is sudoku books tend not to over-reach in terms of difficulty because they're supposed to be accessible to the general public who have usually not progressed beyond all-singles puzzles, and that's to boost sales. i'd recommend you check that the puzzles actually have a unique solution before you solve them, from what you said i think it's more likely that the puzzles are flawed rather than being too hard. i may be wrong though. also i miss borders, shame about it going bankrupt

anything over 9x9 is too much damn hard work