Shapes of needles I use for acupuncture
The most common one is the filiform needle. It is very thin and sharp, and is usually inserted with a guiding tube. This makes the insertion quick and painless.
Depending on the desired result, the needle is removed from its point after a few seconds or is left in place for a few minutes. I don't retain needles often.
Filiform needles can also be used non-insertion techniques for needle-phobic patients. In that case, the tip of the needle just rests on or above the skin but does not puncture the skin.
Japanese techniques require the use of very thin needles: 0.16 mm diameter is the standard gauge, 0.12 mm is the thinnest. That's about as thin as a few hairs next to each other. Figures for comparison: The standard Chinese Acupuncture needle gauge is 0.25 or 0.30 mm. The diameter of a standard intravenous needle used for taking blood samples is 0.8 mm.
Hinaishin or intradermal needle
The Hinaishin is a tiny needle, 3-6 mm long and looks a bit like a question mark with its "head" closed. It is inserted tangentially into the skin and then taped into place to provide gentle but ongoing stimulation to an acupuncture point. Once inserted, the Hinaishin is not felt by the patient. Hinaishin are used on the body and are usually left in place for 3-5 days.
Empishin or perpendicular intradermal needle
Empishin are sometimes called "press tacks" and they do look like tiny thumb-tacks on a bit of sticky tape (the sticky tape is removed in the picture). They are only 1-1.5 mm long and, like the Hinaishin, are used for continuous stimulation of an acupoint.
Empishin are used on ear and body points and are left in place for 2-3 days. Once they are inserted, the Empishin is not felt by the patient.
Lancet for micro-bloodletting
Sometimes I will bleed an acupoint to release "excess". To do this, I sterilise the point with an alcoholic swab, prick it with a lancet (a regular one, like doctors use for blood sugar testing) and squeeze out a few drops of blood. The pricking hurts a little, but this technique gives quick pain relief. A sore throat or tonsillitis, for example, can be greatly relieved within minutes just by pricking two points on the thumbs.