Nanae Kinsei

The sevenfold symmetry extends the somatosensory capabilities of the Shinobi outwards to permeate his environment. Somatosensation literally means "body-sense"; it is the set of senses which originates from the entire body, including skin, bone, muscle and tendon, not limited to the specialized sensory organs of the head.

History
Shodai 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. Near the end of his life, he feared for the future of his clan. He settled the clan near Konoha and instituted a policy of adopting orphaned refugees of the ninja wars and smaller skirmishes in order to replenish the clan’s waning numbers. He initiated the clan into ranching baku and spirit worms. Baku were useful for their extremely hard bones, which could be fashioned into weapons after slaughter. Spirit worms were useful for purging illnesses from the sick. From this practice, he created the dōjutsu seal, implanted the seal on the clansmen, who had the bloodline, and taught those clansmen to use it. However, certain clansmen remained unsuitable for the newfound Kyrgyzishi dōjutsu so the Shodai invented a technique unrelated to dōjutsu that offered enough benefits to deal with the tunnel vision effect created by the high speed movements of the kundalini. He then spread this technique throughout the clansmen and allied clans of his peoples.

Preparations
The seal must be applied by a high level medical nin of the Kyrgyzishi clan to a child subject by the age of six. The neurological rewiring that the somatosensory cortex undergoes when the seal is active will present devastating effects on anyone maladjusted to this process. After the age of six the neurological development of the child is too advanced to acclimate properly to this seal and is best applied well before that time.

An invisible ink, made from fermentation of baku venom and molted husks of lindworm larvae, is injected into the sternum. The eyes of the medical nin are brought near enough to the child’s chest to touch with eyelashes. The clansman then uses his kekkei tōta to activate the dye and tattoo the seal permanently inside the breast bone of the subject.

This is a very delicate operation; a highly skilled medical nin using bio acoustic microscopy is necessary to avoid serious internal injuries to the child. Therefore only a clansman with the bloodline limit can perform this operation. The sealing procedure is also done while the child is anesthetized to avoid any movement that would interfere.

Overview
Somatosensation encompasses proprioception, kinesthesis, and the cutaneous senses, which include temperature, tactile(touch), pressure, and pain reception. Experts refer to these seemingly distinct senses collectively as somatosensation. These body senses link intricately with separate functions operated in distinct structures of the brain.

The visual regions remain separate in structure and function auditory, gustatory, olfactory, as well as, from the somatosensory. However, the somatosensory cortex receives input from all the structures responsible for pain, temperature, touch, proprioception, kinethesis, etc. Consequently, these senses may appear as separate entities upon cursory examination, however, it is their common destination, and subsequent similarity in processing, that has combined them into a gestalt sense which this seal allows the shinobi to manipulate at will.

Primary Effects
When using sevenfold symmetry a shinobi senses his environment as if it were an extension of his body. It is primarily used to detect all motion within a 50 meter radius of the shinobi's location. Whether large or small, any object in motion falls under the skilled users awareness, allowing for swifter reaction time. The most skilled users exhibit the capability of detecting even the smallest and slowest wind currents in their vicinity. He can also glean certain kinds of information from physical objects, such as temperature, texture, etc, as if he were physically in contact with said objects. The sensitivity of this technique allows some shinobi to sense even the heartbeats and blood flow of opponents who are otherwise absolutely still. It is said the Shodaime Oyabun was capable of sensing even the nerve signals traveling from the brain and spinal column of his enemies.

Side Effects
While this passive technique generally creates low stress on the system, overextended use of this technique can result in neurogenic shock. Symptoms include headache, weakness in extremities, debilitating cutaneous pain, phantom sensations, and hypothermia.