Having tried various other Kakuro books and been disappointed by the lack of a challenge I started with the Black Belt version. So far this is the only book I have found where the puzzles are consistently difficult, do not repeat features across the grid, and have unique solutions.
It is definitely NOT one for beginners. The four page introduction takes you step by step through a simple example, and does mention one basic technique overlooked by most books. However you will need to use many more techniques to solve the subsequent puzzles. Even the six warm-up puzzles (9*12 grid) are quite tough, and give a good indication of what to expect on the 144 full size 12*21 challenges.
For those familiar with Sudoku you need to develop techniques of a similar level to pointing pairs, x-wings, xy-chains etc to solve many of these puzzles.
Not the cheapest book in price per puzzle but well worth paying the extra
Overall a very good collection of tough enjoyable challenges for an experienced Kakuro puzzler. Just don't expect to finish them in 5 minutes!