I have downloaded China customs data on imports from the US by HS 8 digit code in 2017 from IHS Markit’s Global Trade Atlas, and caluculated its retaliation values. I have found that Chinese caluculated on HS 8 digit codes, not on 6 digit codes. Based on the US customs data, I had guessed that they calculated on 6, not on 8 digit codes. I was wrong on my guess.