Board Thread:Consensus Track/@comment-1207741-20180718211633/@comment-1207741-20180726222653

There's two levels of official that we're talking about. There are out-of-universe official names, which basically means anything that's used least once in the series. In this case, both "Team 10" and "Team Asuma" are out-of-universe official. Then there's in-universe official names, which, as Sarutobi says, there can only be one of. In this case, "Team 10" is the official/legal/formal name, "Team Asuma" is the unoffical/common/informal name.

For evidence of this, see chapter 3: Iruka, reading from the official team assignments, tells Naruto, Sasuke, and Sakura that they are on "Team 7". It isn't until the next chapter that they even learn Kakashi's name, and it isn't until many chapters later (Part II?) that "Team Kakashi" starts to be used. I realize that this chapter makes no mention of Team 10, but seeing as they hadn't been invented yet we can assume they would've followed the same pattern.

See also chapter 35: during the formal application process for the Chunin Exams, Kakashi, Kurenai and Asuma submit their students' name to the Third Hokage using the team numbers. Given the circumstances, we can assume that the team number is how they are referred to in official matters.

I have a relative named John. This is the name that's on his birth certificate, his driver's license, his bank account, and so on. John is his official name. But he goes by Will. This is the name that he signs letters with, that he uses when introducing himself, that friends know him as, and so on. If I were to try calling him something other than Will, he would give me funny looks. But Will is not his official name.