what's been fun to learn about sumi is that it's a moving target. When SU's first made their appearance, the sumi was so-so. When they were used to create showa, the sumi improved and then was used from showa to re-create shiro utsuri as they had fell in popularity. Since that time the showa's have been infused with sanke sumi and this has stirred the pot. Right now shiro sumi from different breeders can be close to 5 different kinds with different criteria for development. So it really takes an intensive study to get a hand on it. Don't be overwhelmed tho. use the ones in your ponds to learn from. personal observation is a strong study tool...
