Four Divine Beasts Barrier

The Four Divine Beasts Barrier is a barrier ninjutsu of immense power, known only to high ranking shinobi within Yamagakure. It was created by the shinobi team in charge of protecting Yamagakure and then taught to the Yamakage's personal security detail for optimum results.

Overview
The Four Divine Beasts Barrier requires no less than four users with astute chakra control. As such, outside of the Yamakage's personal security detail, only shinobi specifically trained in barrier ninjutsu are properly capable of erecting the barrier. In order to activate the barrier, the four shinobi position themselves at an equal distance apart, in the four cardinal directions, and preform the necessary hand seals. Upon completion, the barrier is raised as a tremendous dome that not only shields the village at ground level, but in a three hundred and sixty degree angle.

The barrier is, for all intents and purposes, impenetrable. According to the First Yamakage, it would take a destructive force of almost twice the power of a Tailed Beast Ball to do damage to the barrier. By pouring their chakra inside this barrier, the users can repair any damage done to it rather quickly.

Unique Qualities
When the Four Divine Beasts Barrier was designed, it was designed as a technique that could accommodate all situations. As a result, it is a highly versatile technique. The barrier gives its four users the ability to sense the chakra of anyone inside, passing through, or in the immediate vicinity of the barrier itself.

Chakra Flow
Using the concept of chakra flow, one of the technique's four users can flow their through the barrier to make it more dangerous. The most common combination is to infuse the barrier with lightning-natured chakra, essentially turning the entire barrier into a massive electrical fence.

Entering/Exiting
Using the barrier's ability to grant the user's access to the sensing of chakra, the users can identify Yamagakure shinobi from outsiders, thereby allowing them to pass through the barrier without any harm coming to them. Outsiders have to gain the approval of the gate guardians before the barrier can be opened for them. Exiting is done in a similar fashion.

Drawbacks
The technique, while one of the most powerful barriers known, has its flaws; however, only two are currently known. When the barrier is erected, four appear where the technique users are situated. These four correspond to a hand seal which must be preformed directly in front of them, in order to release the barrier. The ofuda, and their corresponding hand seals, are;
 * (北) kita → Upside down tiger (called the "tortoise" seal)
 * (南) minami → Bird
 * (東) higashi → Dragon
 * (西) nishi → Tiger

Additionally, as with the technique itself, these four hand seals must be preformed by four separate shinobi (or via the user of a clone technique), in sync with one another. Another weakness of the technique is chakra consumption. The barrier requires tremendous volumes of chakra to maintain, hence why four shinobi are needed to produce it. For this reason, every few hours, an interval which is changed randomly by order of the Yamakage, relief shinobi from the barrier team replace the on-duty shinobi. While the "changing of the guards" doesn't dispel the technique, it does slightly weaken it.

Influences
As with the Four Beasts, this technique was named and designed after the of Chinese astronomy.