The Koi (鯉, Carp) seal is a hand seal unique to the priestess of the Noriko Clan, which is required in techniques that use the unique "pure" Wuji techniques. This seal is formed at the end of such technique to keep the energy in check and mold it into techniques. This seal remains the same when combined with other techniques, such as Sage Chakra (or something resembling it).
The seal resembles the "Tiger" hand seal, but the difference is that the index fingers are wrapped around the middle fingers instead of being hold down like the other fingers.
- Original Idea credit goes to Kai as he created this on the old NF and then gave it to me to use.