Solving guides

Stuck on a hard one? Each guide starts with the rules, then works through the techniques in order from first steps to the tough stuff, with a worked example for each.

• How to solve Sudoku From sole candidates to X-Wings, Swordfish and forcing chains: the techniques that crack hard and extreme puzzles.
• How to solve Calcudoku Cage combinations for + − × ÷, the row and column totals rule, and mixed-operation puzzles.
• How to solve Futoshiki Using the inequality signs: smallest and largest values, ruling out extremes, and chains.