Stop Guessing. Start Solving. The Challenger Series Arrives April 2026
For too long, “Hard” Sudoku puzzles have just been easy puzzles with fewer numbers. They force you to guess. They force you to scribble messy notes. They don’t respect your time.
I am thrilled to announce that in April 2026, we are changing that.
Introducing The Challenger Series (also known as the Espresso Shot collection)—a massive 12-volume anthology designed exclusively for solvers who crave a real cognitive workout.
What is The Challenger Series?
This isn’t a random collection generated by a free app. This is a curated, computer-verified library of logic.
Spanning 12 Volumes, this series is built for those who have mastered the basics and are ready for the deep end.
What’s Inside Each Volume?
Each book in the series is packed with 200 Puzzles:
- 100 Hard Puzzles: Complex intersections and tight logic paths.
- 100 Expert Puzzles: requiring advanced techniques like X-Wings, Swordfish, and Y-Wings.
Why This Series is Different
As a software architect, I approach Sudoku differently. I believe a puzzle is a system, and every system should be bug-free.
- Zero Guessing: Every single grid is mathematically proven to have a unique logical path. You will never have to guess.
- Computer-Verified Difficulty: We use the QQWing logic engine to grade our puzzles. If it says “Expert,” it actually requires expert techniques.
- Designed for Focus: Large print, wide margins, and a layout that respects the “pencil work” required for high-level solving.
Release Schedule
The complete 12-volume set will be available worldwide on Amazon KDP starting April 2026.
Whether you want to test your limits with Volume 1 or collect the entire year’s worth of challenges, get your pencils ready.