Nidan Kohaku (nee-dan co-hakoo) - have 2 patches of beni (hi) or red on the white skin.
Sandan Kohaku (san-dan co-hakoo) - have 3 patches of beni (hi) on the white skin.
Although there are a few Koi that conform to certain criteria, most do not. This Koi is tecnically a Nidan. But as the Koi grows it will become a Sandan as the first Hi plate will break away. But it could also be described as a Inazuma (lightning pattern).
In conclusion all patterns are irrelevant without quality. When buying any Koi, never sacrifice the quality for a particular pattern you are looking for.
