Chijutsu relates to grounding, cultivation of energy and energy embedding. Crystal is a known sub-element of earth and Crystal Technique (Shōjutsu) is a rare and specialized field of Kigata that can create crystal as well as manipulate already-existing crystals and crystalline structures.
Shōjutsu can crystallize any substance, thus, earth, water, and wood techniques are useless against it. Using Shōjutsu, the user can crystallize any physical material and even the moisture in the air around them, turning them into a weapon. In the case of human targets, Shōjutsu can solidify its targets down to the cellular level, imprisoning and even killing the victim should the crystal ever be struck, reducing the mass of crystal and the victim down to crystalline dust.
Shōjutsu, though powerful, has two known weaknesses, the first being that it cannot crystallize either raw spiritual energy as they have no physical mass to crystallize. The second weakness of Shōjutsu is that it is susceptible to a specific sound wave frequency; because crystal requires a very precise build-up of molecules, the proper sound waves can break down the build-up before the crystal can properly form.