That's right, it was that name, though it had nothing to do with the one from his past life. It was simply a ninjutsu that stimulated the body's muscles and nerves to increase burst speed, though it could only burst in an instant, meaning a single strike.
This was a basic ninjutsu among Lightning Release Nintaijutsu. Despite being only D-rank, it was quite practical.
Moreover, ninjutsu ranks didn't directly correlate with power. For instance, Kirigakure's signature ninjutsu, the Hidden Mist Technique, was also only D-rank, yet when used well, it was more useful than many high-ranking ninjutsu.
Tamura Hiroshi regarded this Swift Lightning Flash Technique as a part of Chidori. After all, Chidori had the effect of stimulating speed bursts, but that one was more importantly about the piercing power gathered in the hand, and it stimulated body speed bursts for a longer time, unlike the Swift Lightning Flash Technique which lasted for only an instant and could only burst out a single strike.
Tamura Hiroshi's current chakra quantity and Lightning Release Nature Transformation cultivation level were not yet sufficient to form that kind of concentration, so he could only start with the body-stimulation ability first.
Of course, the pure Swift Lightning Flash Technique didn't require nature transformation since it was just a D-rank nintaijutsu, but it had too many hand seals—a full six—and his current seal-weaving speed was two per second, which meant it took three seconds.
If he could cultivate Lightning Release Nature Transformation to a certain level, he could omit four seals and complete it with just two, greatly enhancing the effect of a sneak attack.
As for the Yang Seal obtained from the Uzumaki clan, that required a foundation of sealing technique knowledge and had very high demands on chakra control, so he didn't qualify yet.