Creating sudoku 1
Creating sudoku 2
Creating sudoku 3
Creating sudoku 4

Solutions for:
Puzzle 1 - Difficulty 171
Short Solution: .............dDb-...b.bTF3........................................
Puzzle 2 - Difficulty 283
Short Solution: .........dbbbbt.bBF17F8..............................................
Puzzle 3 - Difficulty 297
Short Solution: .....d.................DbbbbF9F14.......d..F4.........................
Puzzle 4 - Difficulty 148
Short Solution: ..............d.......-.F5..................................

Click Here for a Legend
 
         .      hidden single
         -      single
         d      hidden double
         D      double
         b      line-block interaction
         B      block-line interaction
         t      hidden triple
         T      triple
         q      quadruple
         Q      hidden quadruple
         X      X-wing
         S      swordfish
         J      jellyfish
         F      forcing chain to a common value with length of forcing chain
         f      forcing chain to a contradiction for one of the branches
         e      forcing chain to the end of the sudoku
         g      guess during backtracking process
         w      last guess turned out to be wrong.
  
         The default order for applying the solution steps is to start with hid-
         den singles and singles before trying to eliminate candidates with hid-
         den  tuples  and tuples from doubles to quadruples. Line-block interac-
         tions are applied between doubles and triples. Then  the  more  complex
         techniques  X-wing,  swordfish  and jellyfish are used and if all these
         fail, forcing chains are tried, before reverting to guessing and start-
         ing a backtracking process.