Eniguma Fūin

Users of The Enigma Seal seek to safe guard their secret clan techniques via unique space-time ninjutsu. By providing the user with a pocket dimension his secret jutsu can remain hidden from his enemies, even sensors and doujutsu users. Although this technique has existed since the time of Shodaime Oyabun, with the advent of kekkei genkai piracy, specifically that of Senju Hashirama, during the last great war, it has acquired ubiquitous use in the Land of Whispering Bone.

Origin
Shodaime Oyabun came to power in his clan sometime before the last two ninja wars. Having reached the height of his abilities he was feared far and wide and worshipped within his clan. However, having suffered slaughter of his people by the Uchiha clan during the Ten Fingers of Blood Stained Hands, he developed anti-piracy techniques to shield against their copying abilities, as he feared for the future of his clan. He initiated the Kyrgyzishi into ranching baku and spirit worms. Baku were useful for their super-hard bones, which could be fashioned into weapons after death. Spirit worms were useful for purging illnesses from the sick. Both of these animals were also prized for their potent chakras. From this practice, he created the space-time seal, implanted the seal on the clansmen, who had the bloodline, and taught those clansmen to use it.

Preparations
Seal must be applied by a high level medical nin. The target receives an injection of invisible dye, made from fermentation of baku venom, molted husks of lindworm larvae, and the blood of the subject. The eyes of the medical nin are brought near enough to the subject’s targeted organ. The clansman then uses his kekkei tōta to activate the dye and tattoo the seal permanently microscopically on the target's chakra network.

This is a very delicate operation; a highly skilled medical nin using bio acoustic microscopy is necessary to avoid serious damage to the subject. Therefore only a clansman with the bloodline limit can perform this operation. The sealing procedure is also done while anesthetized to avoid any disruptive movement. It is unknown how Shodai Oyabun created this technique without actually having the capabilities of the prerequisite dōjutsu. Optional combination seals that link jutsu formula requiring multiple operative units often complete the sealing process with two or more seals placed separately. The seals are written in the subject's blood on a template overlay and then ritsuton is used to flash brand the seal onto the target.

Usage
A sensei commonly activates the jutsu formula. From then on the user has to be taught to utilize this particular seal. Jutsus can be added to the basic formula as needed. Once done the seals remain hidden behind a sealed space-time barrier to any known means of espionage, including all known doujutsu, even that of the clan itself. The barrier serves as a gateway to a sealed pocket dimension, similar to the Kamui dimension. This dimension occupies a sequestered area of subspace and cannot be penetrated without destroying the space-time pocket itself and with it the hidden jutsu formula. This would only occur in the event of the user's death. However, at all times this dimension remains microscopically bridged to the user's chakra network. Thus it remains available to the user alone throughout life keyed to the user's specific chakra signature. Unlike other space-time jutsu, mingling of foreign chakra is prohibited. The presence of even the user's chakra mixed with foreign chakra invading the barrier through the user's chakra network results in repulsion of that chakra.

Execution
The user flows a specific amount of unaltered chakra to the barrier, which absorbs that chakra. Once this occurs the chakra interacts with the hidden jutsu formulas therein. Opponents cannot observe this interaction, as it takes place within a secured region of subspace outside of the normal space-time continuum. Any jutsu formula inside becomes active and executes the jutsu from the sealed dimension. The user acts as the conduit from the dimension to normal space. A dōjutsu, for example, only witnesses unadulterated chakra flowing to a localized region of the chakra pathway system and the effects of the jutsu itself. Its user never observes the jutsu formula and therefore cannot "read through" its formulation.