When you study the games of very strong players, you start to notice a few patterns.
Most players have favourite strategic themes that they employ in game after game. Petrosian saved countless lost positions with a well-timed exchange sacrifice, and Kasparov put many a brave pawn to the sword in return for piece activity. Famously, Pillsbury enjoyed plonking a knight on e5, posting it up with d2-d4 and f2-f4, and launching a kingside attack.
Many world-class players also have a spectacular combination that's associated with them; for example Botvinnik's Ba3!! vs. Capablanca, and Shirov's ...Bh3!! vs. Topalov. Interestingly, some players get to use a rare or surprising tactical device more than once; a case of lightning striking twice. Tactical sequences depend much more on the specific quirks of the position than positional ones, so it seems surprising that they can be 'trademarked' in this way. Doubling rooks on an open file happens almost every game - sacrificing a bishop on an empty square for a passed pawn does not!
A simple example: Morphy was fond of performing an exchange sacrifice on a pinned piece on the second rank. He loved pinning an enemy piece down with his bishop so that the rest of his army could attack it, and was willing to temporarily part with a rook to make it happen.
White's Be2 is in a pin, but is threatening to break out by 1. Bxg4. How can black ensure white will continue to have a pinned piece on e2?
Next, a game that every chess player should be familiar with:
That seems pretty trivial - although the basic tactic was the same, those positions were entirely different. The similarity between the following two royal fork combinations is a lot more striking:
Two queen sacrifices on h8, for two rook-capturing royal knight forks, set ten years apart? What are the chances?! It's true that the queen-sacrifice-followed-by-knight-fork trick is not an uncommon one, but many of the other features of the position are also weirdly similar. Did Petrosian have psychic powers?
My favourite tactical trademark comes from Tal. Ok, I'm cheating a bit - the ideas in both positions are pretty different, but they share an essence (a queen sacrifice and a pawn capturing on g7):
Amazing, right? How could that possibly be replicated, in even the slightest way?
Well, there you go.
These tactics could be named in honour of those who 'trademarked' them. How about the Morphy Mix-up, the Petrosian Pirouette, and the Tal Touchdown?
Maybe you can come up with better names...
What's your tactical trademark?