12 Million Checkmates requires Deep Tactics 4.1 or newer

The checkmate database was created from the entire Chessbase big database. We found the mates at the end of each game and backed up to find the longest one possible. This gave us 350,000+ checkmates from the original 3 million games. We created a program to find all possible ways to mate from the end position which took 18 months on 12 computers. This yielded 12 million mating positions. We discovered that there are 140 ways to mate in the average mate in 4 moves and more than 1,000 ways to mate in checkmates of 6 moves.
Checkmates are mating nets in which one piece can deliver mate while others fence the King in. If the King plays a different fleeing move, the pieces switch in fencing and delivering checkmate. This allows us to select piece pairs and triplets so you can practice mating with combinations of pieces. Our checkmate trainer is realistic and effective because of this.

156,000 tactic puzzles requires Deep Tactics 5.1 or newer and is included in Deep Tactics 6.2.

It is by far the largest collection of puzzles in the world (excluding 12 million checkmates).
Arrows can be used to illustrate the solutions creating pattern recognition quickly. Repetitive practice of hundreds of puzzle patterns an hour accelerates experience creating rapid and measurable tactical skill!