To put it precisely, the Lone Nine Sword was not counted as a sword technique.
Different than other sword techniques, this sword technique itself was not created for attacking others. However, it was not precise to call it a defensive technique either.
It was because that the true form of the Lone Nine Sword was its formlessness.
What was the so-called saying of "To attack, but to not defend?" Regarding the attack, it would let one launch a surprise attack. However, it would allow one to predict enemy’s moves and use the offense as defense.
Thus, to have offense and no defense, in fact, it was to use offense as a form of defense. These two types of moves would alternate with each other.
Although Qin Wushuang did not hold the sword in his hand, he did have an image of the sword inwardly. Each day, he stimulated the sword intention inside his brain. Now, he could be said to have an excellent set of sword skills.