A latin square with greater-than signs: every number once per row and column, and every sign must hold.
Follow chains of signs. In a 5×5 grid, three cells linked as a < b < c mean a is at most 3 and c is at least 3. A cell at the small end of a long chain is often forced to 1 — and that single certainty usually unlocks its whole row.
The signs constrain more than they seem. Before trying numbers, read every chain end to end and note the smallest and largest each cell can still be.
Each futoshiki in Puzelo is checked by a solver written separately from the generator, using a different method. A puzzle is only published if that independent solver finds exactly one solution — so you never need to guess, and the answer we print is never wrong.
More puzzle types: Sudoku · Nonogram · Binary Puzzle · Kakuro