Ha self-published an e-book poetry collection Seoul Si that was downloaded 30,000 times and owned by more than 100,000 readers in ten days.
[3] He introduces himself as a singer songwriter who writes songs with poems out of superfluousness, and he names his music genre "si (poetry)-pop".
[12] Ha communicates with others through social media by writing short poems based on daily lives including relationships, love, and work.
[17] For the ‘writer introduction (jakkasogae in Korean)’ section of his book Ha put the photos of him (jakka, the author), a cow (so), and a dog (gae).
And for the table of contents (mokcha in Korean), he put a photo of a person kicking (cha) someone else's neck (mok).
In the collection, he wrote short poems expressing everyday life, disregarding age, values, religion, regions so that anyone can read and enjoy.