The Sohma Family
Norowareta Ichizoku - The Cursed Clan

Noroi - The Curse

Possessed by the 12shi
Certain members of the Sohma clan are possessed by the different spirits of the jyuunishi (creatures from the Chinese horoscope) and the cat. Under certain circumstances, those who are possessed, transform into their animal forms. After some time, they then return to human form, however, the amount of time it takes to revert to human form is variable.

This curse has continued for several hundred years and the specific circumstances that determine who will be possessed is not clearly understood. Members of the same family are not necessarily more likely to be possessed. Either which way, having family members like Yuki and Ayame being possessed is quite unusual.

Essence of the Unspoken Curse
The curse of the Sohma clan. The curse is separate from the transformation into animal form. The curse that Hatori describes as uncanny and insidious...

A more powerful explanation that comes to mind, for the Sohma members, the inidvidual that casts a dark negativity would be the clan leader, Akito. He reigns over the clan with absolute power, and those who oppose him are violently punished. He especially despises when the possessed members come to love others. His unusual and inexplicable actions - are they the source of the true nature of the curse?

Okite - Commandment

Memory Concealment
Only a small part of the Sohma Clan knows the secret of the 12shi. Using Hatori's ability to manipulate memory, the clan has managed to prevent the having the secret leak outside. Young Yuki's friends had their memories of him blanked out after they unfortunately saw Yuki transform. Momiji's mother had her memory changed and believes Momiji to be another family member's child. Also, Hatori himself, erased his girlfriend's memories of himself. The one to give the order is of course, Akito.

The Jyuunishi's Banquet
The banquet of the 12shi. Talked about in old fables, it, in fact, takes place in the Sohma clan. The solemn event occurs at the main house on New Year's Day and only those possessed by the spirits of the 12shi themselves can attend. There, those possessed by the spirits of the old and new year's 12shi perform a dance.

However, the cat is not permitted to attend. The reason is unknown. No one knows why, just that that's been the custom from long ago.

The rule of the banquet, the fable of determining the 12shi and the curse; could they all be connected in some manner......?

Jyuunishi

Conditions for Transformation
When members of the Sohma clan who are possessed by the spirits of the 12shi are hugged by members of the opposite sex, they transform into their animal form. Parents and family members are no exception. Having one's child that was just born transform the instant you hold them...... Momiji's mother was unable to overcome that shock and continued to reject him. However, hugging members of the opposite sex amongst the 12shi does not lead to any transformation.

Also it becomes more common to transform when the body becomes weak. The snake Ayame can't handle cold very well, such that if the termperature should fall too low, he accidentally transforms. Regardless of situation, given time, they will revert to normal, however, they can't control this themselves.