One of the best ways to study Koi is to compare 2 Koi for their excellence.
Please check your knowledge and skill to compare the two.
I included my answer and explanation, which still help your Koi appreciation even more.
Studying and understanding what makes Koi excellent will provide you with different level of joy in Koi keeping,
Koi shows and Koi talk with your Koi friends.
Mamoru Kodama