Hard Core Futoshiki 400

Hard Core Futoshiki 400 is for experienced solvers who want Futoshiki that makes them work. All 400 puzzles are rated Hard, and they reward careful chains of reasoning from start to finish.

Futoshiki, also called Inequality or More or Less, is a Latin square steered by greater-than and less-than signs. You fill the grid so that every row and column holds each number once, with no boxes, and every sign between neighbouring squares must be true. At this level, the signs are where the real work happens: you'll follow chains of them across the grid, combine them with row and column logic, and rule out values several steps ahead.

The book is printed at 8.5 x 11 inches. It suits solvers who already enjoy Futoshiki and want a steady supply of tough puzzles, with no easy pages to work through first.

If you'd like to build up to this level, start with 600 Futoshiki, which comes in three rising levels from Easy to Hard up to Hard to Extreme. And if you get stuck, our guide to solving Futoshiki covers the techniques you'll need, with worked examples.