Maintain Your Brain Kakuro
by Ted Summerfield
If you find Sudoku too easy to solve, then you’ll love the challenge these 99 Kakuro puzzles provide and their ability to maintain your brain.
More than a dozen different grid shapes, and puzzles progress from easy at the beginning to Masochist at the end.
Kakuro looks easy but it isn't, as you'll discover when you try to solve one of my Masochist level puzzles. Happy puzzling, Ted.