Four-move mates are calculation endurance. The idea is rarely exotic — a king hunt, a battery, a net that tightens square by square — but holding four moves of forcing play in your head, with every branch answered, is real work. That is exactly why they are worth training. Take the featured real-game puzzle below slowly — count your line to the mate before touching a piece — then train longer mates in the trainer at your own level.
Expect long king hunts: a sacrifice drags the king into the open, checks herd it up the board, and a quiet fourth move ends a journey that started in the castled corner somewhere in the middle of your camp. Expect move-order traps too — many mate-in-4 positions contain a tempting sequence that mates in five instead, and only the precise order gets there in four. The tightening mating net is the recurring shape; the finishing blows are the classic patterns under checkmate in the glossary.
If your comfortable calculation horizon is two moves, forced four-move lines stretch it the honest way: with immediate feedback and no engine crutch. Candidate moves, the opponent's best defense, and a written-in-your-head tree — the same discipline that wins won positions over the board.
Build the tree in layers: choose a forcing first move, answer the toughest defense first, and reuse finishes — most branches converge on the same final pattern. Naming the target pattern early ("this is a ladder", "this is a net around a cornered king") compresses four moves of branches into one idea plus details.
There is no entry ticket — the featured positions here sit in the 1000–1800 band, and a patient intermediate player can solve them by pure method. What rises with rating is speed and reliability under branching, which is precisely the muscle these puzzles exist to build.
Because the skill is transferable depth, not the mates themselves. Every long endgame line, defensive save and winning attack leans on holding several forced moves in your head with all defenses answered. Forced mates are the cleanest possible practice: the goal is unambiguous and the feedback immediate.