Tactics
The forcing motifs — forks, pins, skewers, discovered attacks and more — that win material or the game outright.
Decoy
Deflection's twin: instead of luring a defender away, lure a piece (often the king) onto a square where a follow-up tactic destroys it.
Deflection
Forcing a key defending piece away from the square or line it is protecting, even at the cost of material, so a bigger threat can land unopposed.
Discovered Attack
Moving one piece out of the way reveals an attack from a piece behind it — meaning the moving piece gets a free tempo to do something else entirely.
Double Attack
The broad family every fork and skewer belongs to: a single move creating two simultaneous threats, so the defender can only deal with one.
Fork
A single piece attacking two (or more) enemy targets at the same time, so at least one of them cannot be saved.
Pin
Immobilizing an enemy piece by attacking it from behind a more valuable piece (or the king) that cannot afford to move out of the way.
Skewer
The pin's mirror image: attack a valuable piece that must move, exposing a less valuable piece directly behind it to capture.
Windmill (Seesaw)
A repeating discovered-check combination where a rook and bishop battery swings back and forth, devouring material on every single swing.
Zwischenzug (In-Between Move)
German for "in-between move": inserting an unexpected threat before making the recapture or reply everyone assumed was automatic.