This is the solution to the Sudoku Hard Puzzle. Each number found is followed by a dash and then a two-digit sequence number, which is the sequence in which I found the numbers. You may find some of them in a different order. If you get to one that puzzles you (how did he find that?), consider both Phantom Find and Exclusion using What's Left Lists. Or look for Isolation in a junction using companion boxes. The first one found was (2,2)=8, then (8,5)=8, etc. ||=====|=====|=====||=====|=====|=====||=====|=====|=====|| || | 7-17| || 1-30| | 3-31|| | 6-18| 5-29|| || 2 | | 9 || | 4 | || 8 | | || ||-----|-----|-----||-----|-----|-----||-----|-----|-----|| || | 8-01| 4-05|| | 5-26| 2-27|| 1-25| 7-24| 3-28|| || 6 | | || 9 | | || | | || ||-----|-----|-----||-----|-----|-----||-----|-----|-----|| || | 3-16| 5-14|| | 7-15| 6-19|| 2-20| | || || 1 | | || 8 | | || | 4 | 9 || ||=====|=====|=====||=====|=====|=====||=====|=====|=====|| || 9-34| | 2-53|| 5-42| 1-33| 4-41|| | | 7-52|| || | 6 | || | | || 3 | 8 | || ||-----|-----|-----||-----|-----|-----||-----|-----|-----|| || 5-45| 4-37| 7-54|| 2-49| | 8-47|| 6-39| 9-23| 1-40|| || | | || | 3 | || | | || ||-----|-----|-----||-----|-----|-----||-----|-----|-----|| || 8-46| | || 6-50| 9-32| 7-48|| 4-38| | 2-51|| || | 1 | 3 || | | || | 5 | || ||=====|=====|=====||=====|=====|=====||=====|=====|=====|| || | | 1-04|| 4-07| 6-10| || 5-09| 3-08| || || 7 | 2 | || | | 9 || | | 8 || ||-----|-----|-----||-----|-----|-----||-----|-----|-----|| || 3-12| 5-13| 6-11|| 7-03| 8-02| || 9-21| 2-22| || || | | || | | 1 || | | 4 || ||-----|-----|-----||-----|-----|-----||-----|-----|-----|| || 4-36| 9-35| || 3-44| | 5-43|| | 1-06| || || | | 8 || | 2 | || 7 | | 6 || ||=====|=====|=====||=====|=====|=====||=====|=====|=====||