FirstKlass made "Letter to My Younger Brother" available on May 13, 2020. Letter to My Younger Brother is 2 minutes and 55 seconds long and may contain bad words that may be unsuitable for children. Because this song is the only song in Letter to My Younger Brother and no other songs are present in the album, we classify this track as a single. Based on our statistics, Letter to My Younger Brother's popularity is unknown right now. Since there is more of a neutral sound being played, this makes the track somewhat danceable.
We consider the tempo marking of Letter to My Younger Brother by FirstKlass to be Vivace (lively and fast) because the track has a tempo of 157 テンポ, a half-time of 78テンポ, and a double-time of 314 テンポ. Based on that, the speed of the song's tempo is fast. Activities such as, running, can go well with this song. The time signature for this track is 4/4.
B♭ Minor is the music key of this track. Because this track belongs in the B♭ Minor key, the camelot key is 3A. So, the perfect camelot match for 3A would be either 3A or 2B. While, a low energy boost can consist of either 3B or 4A. For moderate energy boost, you would use 12A and a high energy boost can either be 5A or 10A. However, if you are looking for a low energy drop, finding a song with a camelot key of 2A would be a great choice. Where 6A would give you a moderate drop, and 1A or 8A would be a high energy drop. Lastly, 6B allows you to change the mood.