In the annotations of the Hidden Weapons Hundred Solutions, the Longxu needle is described as such: especially effective against internal Vigorous Qi, requiring sufficient Inner Strength to launch, catching the enemy off guard and inflicting immense pain. However, the materials are difficult to obtain, and the consumption of Inner Strength is considerable, requiring enough support from Inner Strength for continuous use.
With Tang San's current level of Inner Strength, he could only ensure the Longxu needle's attack power within a three-meter range. Beyond that, the Longxu needle would retract due to insufficient Inner Strength before even hitting the enemy. And as the attack distance increased, the requirement for Inner Strength would also become more demanding. This powerful and domineering hidden weapon was not so easy to wield.