Small book. Serious challenge. The Pretty Pocket Sudoku – Hard Edition is designed for solvers who love a deeper logic workout but still want their puzzles wrapped in beauty and calm. Featuring a dreamy vintage undersea cover , this compact 4×6 pocket-size book brings the mystery and depth of the ocean to your everyday puzzle ritual. Inside are 100 hard Sudoku puzzles , each printed in clear, large type and placed on its own page for maximum focus. The layout keeps things clean and uncluttered, even when the challenge ramps up, making it ideal for concentrated solving wherever you are. Perfect for travel, cafés, waiting rooms, or quiet evenings, this tiny book proves that big thinking doesn’t need a big format. 🌊 Vintage undersea cover with calm, immersive coastal charm 🧩 100 hard-level puzzles for focused, satisfying brain training 📘 Large print for comfortable solving in a compact book 👜 Ultra-portable 4×6 size that fits easily in pockets and purses 📄 One puzzle per page for clarity and deep concentration ✔️ Solutions included at the back for checking and learning 🕰️ Screen-free mental workout that sharpens focus while encouraging calm Challenging, compact, and beautifully designed, this Pretty Pocket Sudoku is the perfect companion for puzzle lovers who want their brain training to feel both rewarding and serene.