The phrase "a special technique" is correct and usable in written English.
You can use it when referring to a specific method or approach that is unique or particularly effective in a certain context.
Example: "The artist employed a special technique to create the stunning visual effects in her paintings."
Alternatives: "a unique method" or "an exclusive approach."
He had a special technique.
Printed using a special technique that ensures the print doesn't stretch or fade.
In seeking the solutions of problems, geometers developed a special technique, which they called "analysis".
'A Dismal Record' In one case, the officer explained that he had a special technique for detecting who was hiding a gun.
Ground sluicing is a special technique for the mining of natural placers as well as artificial ones (tailings piles, for example).
Sir Richard enthuses about Affymax, a Californian firm that he bought two years ago, and which has developed a special technique for screening chemical compounds for their usefulness.
Schlieren is German for "streaks"; in this case it refers to regions of different densities in a gas or a liquid, which can be photographed as shadows using a special technique.
They need to master a special technique to hold their partner at arm's length, explains Royal Ballet principal Edward Watson, "because if you get up too close, you squash the woman's skirt".
Ujima has to use a special technique for "proving" the dough – letting it rest so the yeast can make it rise – to help preserve the loaves in Kenya's heat, but otherwise the bread-making process is the same.
(Bracteates were lightweight silver coins so thin that they bore only a single type, repoussé [hammered into relief on the reverse], for which a special technique [including the use of wooden dies] was devised).
A few years ago, a group of Colombians near the triple frontier with Peru and Brazil taught at least two Brazilians a special technique in which they submerge a gloved hand into the water holding pieces of dead dolphin bones.
