The Hougetsu Jigen-Tou (崩月次元刀, Moon Crushing Dimensional Sword) is a special dark arts technique that was developed by Touhou Fuhai, one of the Three Dark Lords. It is a dangerous technique that should not be taken lightly.
To use it, the user utilizes his or her hand by flattening it out with all fingers next to each other leaving no gaps between them. The hand is then used like a sword and is slashed towards the intended target. it allows the user to "postpone the dimension in which they exist" and enables them to go through all matter and create the "ultimate blade". Touhou Fuhai tells Tsukune that this technique is like a saw, moving back and forth between dimensions, which means that it cannot cut if it cannot move.
Defensively, the Jigen-Tou can be used to postpone the dimension of the user's entire body, allowing them to pass through walls and nullify an enemy's attacks.
When a person is skilled enough with the Jigen-Tou, they can hit a target from long-range without the need to make contact. However, this is a great feat and only two individuals, Touhou Fuhai and Akua Shuzen have managed to reach this level.
The only thing that can stop a Jigen-Tou is another Jigen-Tou used to parry it, much like a sword blocking a strike from another.
After using the Jigen-Tou defensively, it is supposed to leave a forty-second opening during which the user will be unable to attack. This was revealed to Mizore and Kurumu in an attempt to tell them one of Akua's weaknesses, though Akua survived their attack and defeated them.
Later on, it is revealed that a new technique, known as Muei-Tou (無影刀, lit. "Shadowless Sword") or the Tonfa of Light, can prevent the Jigen Tou from traveling between dimensions and stopping it like a saw that cannot be pulled.
The original creator of the technique, he is proficient at it. In fact, he has perfected his to the point where making contact with the target is unnecessary to make a hit. All he has to do is slash in the direction of his intended target and the cut travels the distance to it at lightning speed, with the same end result. Aside from him, only Akua Shuzen is capable of this feat and is as proficient as him with the technique. Gyokuro Shuzen may or may not be capable of a similar feat, as seen in her battle with Tsukune Aono.
Touhou Fuhai's direct apprentice, she is well versed in the Jigen-Tou. However, Ling-Ling is not as skilled with this ability as her mentor or as Akua Shuzen because she needs to make direct contact with her target. However, her version is strong enough to parry Akua, which implies that her skills with this technique are still high enough to not underestimate her.
Akua's skill with the Jigen-Tou is remarkable, having matched Touhou Fuhai's proficiency with the attack. Capable of hitting a target from long range, she is one of only two (maybe three) people capable of this feat, the only other being the technique's creator Touhou Fuhai.
In fact, she is so well versed in this technique that Touhou Fuhai himself observed that she had essentially made the technique her own.
Gyokuro's unique detection ability "Enemy Zero" has allowed her to replicate the Jigen-Tou, the "most evil of blades" by her reckoning, with no difficulty. She may be capable of attacking from a distance, much like her stepdaughter Akua.