He feels his Queens borough president run this year laid the groundwork for a shot at the District 20 seat.
He joins a battle that now has five participants, including four Chinese Americans and one Korean American.
And the competition could be getting more intense as several other members of the Chinese community consider running.
Yin says he thought about running for the City Council a few years ago.
Koo succeeded John Liu, who became the first Asian American on the Council when he was elected in 2001.